Size-exclusion chromatography comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-08-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
Collagen peptides are short chains of amino acids produced by hydrolyzing collagen from animal connective tissues. The parent protein occurs in skin, bone, tendons, and cartilage, where it provides tensile strength. Hydrolysis breaks native triple-helical structures into smaller fragments, improving solubility in water. The resulting mixture consists mainly of glycine, proline, hydroxyproline, and other residues. Commercial ingredients are often described by average molecular weight rather than a single defined molecule.
Industrial production typically begins with raw materials such as bovine hide, porcine skin, fish skin, or eggshell membrane. A pretreatment step removes fat and non-collagenous proteins, after which enzymes or acid/alkali conditions cleave peptide bonds. Manufacturers then purify, concentrate, and dry the hydrolysate into a powder. The degree of hydrolysis influences peptide length, solubility, and taste. Because source and process vary, two collagen peptide powders can differ in amino acid profile and molecular weight distribution.
In nutrition and food science, collagen peptides are discussed as a protein source rather than a complete protein. They lack sufficient amounts of some essential amino acids, notably tryptophan, so they cannot alone support all protein requirements. Research often examines their functional properties, such as foam formation, emulsification, and water binding. Studies also compare bioavailability and absorption of small peptides versus free amino acids. Questions remain about how consistently specific peptide sequences reach target tissues after ingestion.
Collagen is a structural protein found in skin, bone, tendon, and cartilage, where it forms a triple helix of three polypeptide chains. The chains contain repeating Gly-X-Y sequences, with proline and hydroxyproline frequently occupying the X and Y positions. Collagen peptides are fragments produced by breaking these long chains through hydrolysis. These fragments vary in length and amino acid composition depending on the source and processing method, so the term covers a range of products rather than a single defined molecule.
Hydrolysis converts native collagen into shorter peptides and improves water solubility. Enzymatic treatment with proteases such as pepsin or alkaline proteases is common, though acid or thermal hydrolysis can also be used. The resulting molecular weight distribution typically ranges from about 2 to 10 kilodaltons. Gelatin is a related product formed by partial hydrolysis, but it retains the ability to gel in water. Collagen peptides undergo further breakdown and generally do not form gels.
Commercial collagen peptides come from bovine hide, porcine skin, fish scales, and fish skin. Each source yields a distinct amino acid profile, including different levels of hydroxyproline and glycine. Marine sources often have lower hydroxyproline content than mammalian sources. Production involves extraction, hydrolysis, filtration, and drying, usually spray drying. The final powder is typically white to off-white and dissolves readily in water. Exact composition and peptide size depend on the raw material and the hydrolysis conditions.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Hydrolyzed collagen, collagen hydrolysate, gelatin hydrolysate | Peptide and hydrolysate are often used interchangeably. |
| Typical sources | Bovine hide, porcine skin, fish skin, eggshell membrane | Source affects amino acid profile and labeling. |
| Appearance | White to off-white powder | Color can vary slightly with raw material and processing. |
| Solubility class | Water-soluble | Dissolves in cold or warm water better than native collagen. |
| Average molecular weight | Typically 1–10 kDa | Values depend on hydrolysis conditions and measurement method. |
Collagen peptides are short chains of amino acids derived from collagen, the main structural protein in connective tissues. They are produced by hydrolysis, which breaks the triple-helical structure of native collagen into smaller fragments. The resulting peptides typically have molecular weights between 2,000 and 10,000 daltons, though commercial preparations vary. Unlike intact collagen, these peptides are water-soluble and do not form gels at room temperature. The term "collagen peptide" often refers to a mixture of fragments rather than a single defined molecule.
Amino acid composition of collagen peptides reflects that of the parent collagen, with glycine, proline, and hydroxyproline being particularly abundant. Glycine appears at nearly every third residue in the repeating sequence Gly-X-Y, where X and Y are often proline or hydroxyproline. This pattern is partly retained in short peptides, though hydrolysis can cleave at various sites. Hydroxyproline is uncommon in most other proteins and serves as a marker for collagen-derived material. The presence of these amino acids contributes to the unique properties of collagen peptides, including their resistance to certain proteases.
Stability depends on moisture, temperature, oxygen, and packaging. Dry collagen peptide powders are generally stable when kept cool and dry, but humid conditions can cause clumping and microbial growth. Heat exposure may promote Maillard reactions if reducing sugars are present, altering color and flavor. Solutions are less stable than powders and may support microbial proliferation unless preserved or refrigerated; light exposure can also affect appearance over time. Shelf-life claims vary and should be supported by real-time or accelerated stability data.
Quality control for collagen peptides may include identity, purity, and contaminant testing. Identity can be supported by amino acid profile and hydroxyproline content; purity checks may examine moisture, ash, protein content, and peptide size range. Heavy metals, microbial counts, and residual solvents are relevant for materials intended for ingestion. Some suppliers use peptide fingerprinting or source-specific markers, though these methods are not universally standardized. Documentation such as certificates of analysis helps verify that a batch meets agreed specifications.
=== Structural convergence === Here is a list of examples in which unrelated proteins have similar tertiary structures but different functions. Whole protein structural convergence is not thought to occur but some convergence of pockets and secondary structural elements have been documented.
Now EC 1.1.1.303, diacetyl reductase [(R)-acetoin forming] and EC 1.1.1.304, diacetyl reductase [(S)-acetoin forming] EC 1.1.1.6: glycerol dehydrogenase EC 1.1.1.7: propanediol-phosphate dehydrogenase EC 1.1.1.8: glycerol-3-phosphate dehydrogenase (NAD+) EC 1.1.1.9: D-xylulose reductase EC 1.1.1.10: L-xylulose reductase EC 1.1.1.11: D-arabinitol 4-dehydrogenase EC 1.1.1.12: L-arabinitol 4-dehydrogenase EC 1.1.1.13: L-arabinitol 2-dehydrogenase EC 1.1.1.14: L-iditol 2-dehydrogenase EC 1.1.1.15: D-iditol 2-dehydrogenase EC 1.1.1.16: galactitol 2-dehydrogenase EC 1.1.1.17: mannitol-1-phosphate 5-dehydrogenase EC 1.1.1.18: inositol 2-dehydrogenase EC 1.1.1.19: glucuronate reductase EC 1.1.1.20: glucuronolactone reductase EC 1.1.1.207: (-)-menthol dehydrogenase EC 1.1.1.208: (+)-neomenthol dehydrogenase EC 1.1.1.21: aldose reductase EC 1.1.1.22: UDP-glucose 6-dehydrogenase EC 1.1.1.222: (R)-4-hydroxyphenyllactate dehydrogenase EC 1.1.1.23: histidinol dehydrogenase| EC 1.1.1.24: quinate/shikimate dehydrogenase (NAD+) EC 1.1.1.25: shikimate dehydrogenase (NADP+) EC 1.1.1.26: glyoxylate reductase EC 1.1.1.27: L-lactate dehydrogenase EC 1.1.1.28: D-lactate dehydrogenase EC 1.1.1.29: glycerate dehydrogenase EC 1.1.1.30: 3-hydroxybutyrate dehydrogenase EC 1.1.1.31: 3-hydroxyisobutyrate dehydrogenase EC 1.1.1.32: mevaldate reductase EC 1.1.1.33: mevaldate reductase (NADPH) EC 1.1.1.34: hydroxymethylglutaryl-CoA reductase (NADPH) EC 1.1.1.35: 3-hydroxyacyl-CoA dehydrogenase EC 1.1.1.36: acetoacetyl-CoA reductase EC 1.1.1.37: malate dehydrogenase EC 1.1.1.38: malate dehydrogenase (oxaloacetate-decarboxylating) EC 1.1.1.39: malate dehydrogenase (decarboxylating) EC 1.1.1.40: malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) EC 1.1.1.41: isocitrate dehydrogenase (NAD+) EC 1.1.1.42: isocitrate dehydrogenase (NADP+) EC 1.1.1.43: phosphogluconate 2-dehydrogenase EC 1.1.1.44: phosphogluconate dehydrogenase (NADP+-dependent, decarboxylating) EC 1.1.1.45: L-gulonate 3-dehydrogenase EC 1.1.1.46: L-arabinose 1-dehydrogenase EC 1.1.1.47: glucose 1-dehydrogenase [NAD(P)+)] EC 1.1.1.48: D-galactose 1-dehydrogenase EC 1.1.1.49: glucose-6-phosphate dehydrogenase (NADP+) EC 1.1.1.50: 3α-hydroxysteroid 3-dehydrogenase (Si-specific) EC 1.1.1.51: 3(or 17)β-hydroxysteroid dehydrogenase EC 1.1.1.52: 3α-hydroxycholanate dehydrogenase (NAD+) EC 1.1.1.53: 3α(or 20β)-hydroxysteroid dehydrogenase EC 1.1.1.54: allyl-alcohol dehydrogenase EC 1.1.1.55: lactaldehyde reductase (NADPH) EC 1.1.1.56: ribitol 2-dehydrogenase EC 1.1.1.57: fructuronate reductase EC 1.1.1.58: tagaturonate reductase EC 1.1.1.59: 3-hydroxypropionate dehydrogenase EC 1.1.1.60: 2-hydroxy-3-oxopropionate reductase EC 1.1.1.61: 4-hydroxybutyrate dehydrogenase EC 1.1.1.62: 17β-estradiol 17-dehydrogenase EC 1.1.1.63: testosterone 17β-dehydrogenase. Now EC 1.1.1.239, 3α(17β)-hydroxysteroid dehydrogenase (NAD+) EC 1.1.1.64: testosterone 17β-dehydrogenase (NADP+) EC 1.1.1.65: pyridoxine 4-dehydrogenase EC 1.1.1.66: ω-hydroxydecanoate dehydrogenase EC 1.1.1.67: mannitol 2-dehydrogenase EC 1.1.1.68: 5,10-methylenetetrahydrofolate reductase. Now EC 1.5.1.20, methylenetetrahydrofolate reductase [NAD(P)H] EC 1.1.1.69: gluconate 5-dehydrogenase EC 1.1.1.70: D-glucuronolactone dehydrogenase. Now included with EC 1.2.1.3 aldehyde dehydrogenase (NAD+) EC 1.1.1.71: alcohol dehydrogenase [NAD(P)+] EC 1.1.1.72: glycerol dehydrogenase (NADP+) EC 1.1.1.73: octanol dehydrogenase EC 1.1.1.74: D-aminopropanol dehydrogenase (reaction due to EC 1.1.1.4 (R,R)-butanediol dehydrogenase) EC 1.1.1.75: (R)-aminopropanol dehydrogenase EC 1.1.1.76: (S,S)-butanediol dehydrogenase EC 1.1.1.77: lactaldehyde reductase EC 1.1.1.78: methylglyoxal reductase (NADH-dependent) EC 1.1.1.79: glyoxylate reductase (NADP+) EC 1.1.1.80: isopropanol dehydrogenase (NADP+) EC 1.1.1.81: hydroxypyruvate reductase EC 1.1.1.82: malate dehydrogenase (NADP+) EC 1.1.1.83: D-malate dehydrogenase (decarboxylating) EC 1.1.1.84: dimethylmalate dehydrogenase EC 1.1.1.85: 3-isopropylmalate dehydrogenase EC 1.1.1.86: ketol-acid reductoisomerase (NADP+) EC 1.1.1.87: homoisocitrate dehydrogenase EC 1.1.1.88: hydroxymethylglutaryl-CoA reductase EC 1.1.1.89: dihydroxyisovalerate dehydrogenase (isomerizing). Now included with EC 1.1.1.86 ketol-acid reductoisomerase EC 1.1.1.90: aryl-alcohol dehydrogenase EC 1.1.1.91: aryl-alcohol dehydrogenase (NADP+) EC 1.1.1.92: oxaloglycolate reductase (decarboxylating) EC 1.1.1.93: tartrate dehydrogenase EC 1.1.1.94: glycerol-3-phosphate dehydrogenase [NAD(P)+] EC 1.1.1.95: phosphoglycerate dehydrogenase EC 1.1.1.96: diiodophenylpyruvate reductase EC 1.1.1.97: 3-hydroxybenzyl-alcohol dehydrogenase EC 1.1.1.98: (R)-2-hydroxy-fatty-acid dehydrogenase EC 1.1.1.99: (S)-2-hydroxy-fatty-acid dehydrogenase EC 1.1.1.100: 3-oxoacyl-[acyl-carrier-protein] reductase EC 1.1.1.101: acylglycerone-phosphate reductase EC 1.1.1.102: 3-dehydrosphinganine reductase EC 1.1.1.103: L-threonine 3-dehydrogenase EC 1.1.1.104: 4-oxoproline reductase EC 1.1.1.105: all-trans-retinol dehydrogenase (NAD+) EC 1.1.1.106: pantoate 4-dehydrogenase EC 1.1.1.107: pyridoxal 4-dehydrogenase EC 1.1.1.108: carnitine 3-dehydrogenase EC 1.1.1.109: Now EC 1.3.1.28, 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase EC 1.1.1.110: aromatic 2-oxoacid reductase EC 1.1.1.111: 3-(imidazol-5-yl)lactate dehydrogenase EC 1.1.1.112: indanol dehydrogenase EC 1.1.1.113: L-xylose 1-dehydrogenase EC 1.1.1.114: apiose 1-reductase EC 1.1.1.115: ribose 1-dehydrogenase (NADP+) EC 1.1.1.116: D-arabinose 1-dehydrogenase (NAD+) EC 1.1.1.117: D-arabinose 1-dehydrogenase [NAD(P)+] EC 1.1.1.118: glucose 1-dehydrogenase (NAD+) EC 1.1.1.119: glucose 1-dehydrogenase (NADP+) EC 1.1.1.120: galactose 1-dehydrogenase (NADP+) EC 1.1.1.121: aldose 1-dehydrogenase (NAD+) EC 1.1.1.122: D-threo-aldose 1-dehydrogenase EC 1.1.1.123: sorbose 5-dehydrogenase (NADP+) EC 1.1.1.124: fructose 5-dehydrogenase (NADP+) EC 1.1.1.125: 2-deoxy-D-gluconate 3-dehydrogenase EC 1.1.1.126: 2-dehydro-3-deoxy-D-gluconate 6-dehydrogenase EC 1.1.1.127: 2-dehydro-3-deoxy-D-gluconate 5-dehydrogenase EC 1.1.1.128: The reaction described is covered by EC 1.1.1.264, L-idonate 5-dehydrogenase. EC 1.1.1.129: L-threonate 3-dehydrogenase EC 1.1.1.130: 3-dehydro-L-gulonate 2-dehydrogenase EC 1.1.1.131: mannuronate reductase EC 1.1.1.132: GDP-mannose 6-dehydrogenase EC 1.1.1.133: dTDP-4-dehydrorhamnose reductase EC 1.1.1.134: dTDP-6-deoxy-L-talose 4-dehydrogenase (NADP+) EC 1.1.1.135: GDP-6-deoxy-D-talose 4-dehydrogenase EC 1.1.1.136: UDP-N-acetylglucosamine 6-dehydrogenase EC 1.1.1.137: ribitol-5-phosphate 2-dehydrogenase EC 1.1.1.138: mannitol 2-dehydrogenase (NADP+) EC 1.1.1.139: polyol dehydrogenase (NADP+). Now included with EC 1.1.1.21 aldehyde reductase EC 1.1.1.140: sorbitol-6-phosphate 2-dehydrogenase EC 1.1.1.141: 15-hydroxyprostaglandin dehydrogenase (NAD+) EC 1.1.1.142: D-pinitol dehydrogenase EC 1.1.1.143: sequoyitol dehydrogenase EC 1.1.1.144: perillyl-alcohol dehydrogenase EC 1.1.1.145: 3β-hydroxy-Δ5-steroid dehydrogenase EC 1.1.1.146: 11β-hydroxysteroid dehydrogenase EC 1.1.1.147: 16α-hydroxysteroid dehydrogenase EC 1.1.1.148: estradiol 17α-dehydrogenase EC 1.1.1.149: 20α-hydroxysteroid dehydrogenase EC 1.1.1.150: 21-hydroxysteroid dehydrogenase (NAD+) EC 1.1.1.151: 21-hydroxysteroid dehydrogenase (NADP+) EC 1.1.1.152: 3α-hydroxy-5β-androstane-17-one 3α-dehydrogenase EC 1.1.1.153: sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming) EC 1.1.1.154: ureidoglycolate dehydrogenase EC 1.1.1.155: homoisocitrate dehydrogenase. The enzyme is identical to EC 1.1.1.87, homoisocitrate dehydrogenase EC 1.1.1.156: glycerol 2-dehydrogenase (NADP+) EC 1.1.1.157: 3-hydroxybutyryl-CoA dehydrogenase EC 1.1.1.158: Now EC 1.3.1.98, UDP-N-acetylmuramate dehydrogenase EC 1.1.1.159: 7α-hydroxysteroid dehydrogenase EC 1.1.1.160: dihydrobunolol dehydrogenase EC 1.1.1.161: The activity is part of EC 1.14.13.15, cholestanetriol 26-monooxygenase EC 1.1.1.162: erythrulose reductase EC 1.1.1.163: cyclopentanol dehydrogenase EC 1.1.1.164: hexadecanol dehydrogenase EC 1.1.1.165: 2-alkyn-1-ol dehydrogenase EC 1.1.1.166: hydroxycyclohexanecarboxylate dehydrogenase EC 1.1.1.167: hydroxymalonate dehydrogenase EC 1.1.1.168: 2-dehydropantolactone reductase (Re-specific) EC 1.1.1.169: 2-dehydropantoate 2-reductase EC 1.1.1.170: 3β-hydroxysteroid-4α-carboxylate 3-dehydrogenase (decarboxylating) EC 1.1.1.171: Now EC 1.5.1.20, methylenetetrahydrofolate reductase [NAD(P)H] EC 1.1.1.172: 2-oxoadipate reductase EC 1.1.1.173: L-rhamnose 1-dehydrogenase EC 1.1.1.174: cyclohexane-1,2-diol dehydrogenase EC 1.1.1.175: D-xylose 1-dehydrogenase EC 1.1.1.176: 12α-hydroxysteroid dehydrogenase EC 1.1.1.177: glycerol-3-phosphate 1-dehydrogenase (NADP+) EC 1.1.1.178: 3-hydroxy-2-methylbutyryl-CoA dehydrogenase EC 1.1.1.179: D-xylose 1-dehydrogenase (NADP+, D-xylono-1,5-lactone-forming) EC 1.1.1.180: Now included with EC 1.1.1.131 mannuronate reductase EC 1.1.1.181: cholest-5-ene-3β,7α-diol 3β-dehydrogenase EC 1.1.1.182: Now included with EC 1.1.1.198 (+)-borneol dehydrogenase, EC 1.1.1.227 (-)-borneol dehydrogenase and EC 1.1.1.228 (+)-sabinol dehydrogenase EC 1.1.1.183: geraniol dehydrogenase (NADP+) EC 1.1.1.184: carbonyl reductase (NADPH) EC 1.1.1.185: L-glycol dehydrogenase EC 1.1.1.186: dTDP-galactose 6-dehydrogenase EC 1.1.1.187: GDP-4-dehydro-D-rhamnose reductase EC 1.1.1.188: prostaglandin-F synthase EC 1.1.1.189: prostaglandin-E2 9-reductase EC 1.1.1.190: indole-3-acetaldehyde reductase (NADH) EC 1.1.1.191: indole-3-acetaldehyde reductase (NADPH) EC 1.1.1.192: long-chain-alcohol dehydrogenase EC 1.1.1.193: 5-amino-6-(5-phosphoribosylamino)uracil reductase EC 1.1.1.194: coniferyl-alcohol dehydrogenase EC 1.1.1.195: cinnamyl-alcohol dehydrogenase EC 1.1.1.196: 15-hydroxyprostaglandin-D dehydrogenase (NADP+) EC 1.1.1.197: 15-hydroxyprostaglandin dehydrogenase (NADP+) EC 1.1.1.198: (+)-borneol dehydrogenase EC 1.1.1.199: (S)-usnate reductase EC 1.1.1.200: aldose-6-phosphate reductase (NADPH) EC 1.1.1.228: (+)-sabinol dehydrogenase EC 1.1.1.251: galactitol-1-phosphate 5-dehydrogenase EC 1.1.1.252: tetrahydroxynaphthalene reductase EC 1.1.1.253: Now EC 1.5.1.33, pteridine reductase EC 1.1.1.254: (S)-carnitine 3-dehydrogenase EC 1.1.1.255: mannitol dehydrogenase EC 1.1.1.256: fluoren-9-ol dehydrogenase EC 1.1.1.257: 4-(hydroxymethyl)benzenesulfonate dehydrogenase EC 1.1.1.258: 6-hydroxyhexanoate dehydrogenase EC 1.1.1.259: 3-hydroxypimeloyl-CoA dehydrogenase EC 1.1.1.260: sulcatone reductase EC 1.1.1.261: sn-glycerol-1-phosphate dehydrogenase EC 1.1.1.262: 4-hydroxythreonine-4-phosphate dehydrogenase EC 1.1.1.263: 1,5-anhydro-D-fructose reductase EC 1.1.1.264: L-idonate 5-dehydrogenase EC 1.1.1.265: 3-methylbutanal reductase EC 1.1.1.266: dTDP-4-dehydro-6-deoxyglucose reductase EC 1.1.1.267: 1-deoxy-D-xylulose-5-phosphate reductoisomerase EC 1.1.1.268: 2-(R)-hydroxypropyl-CoM dehydrogenase EC 1.1.1.269: 2-(S)-hydroxypropyl-CoM dehydrogenase EC 1.1.1.270: 3β-hydroxysteroid 3-dehydrogenase EC 1.1.1.271: GDP-L-fucose synthase EC 1.1.1.272: D-2-hydroxyacid dehydrogenase (NADP+) EC 1.1.1.273: vellosimine dehydrogenase EC 1.1.1.274: 2,5-didehydrogluconate reductase (2-dehydro-D-gluconate-forming) EC 1.1.1.275: (+)-trans-carveol dehydrogenase EC 1.1.1.276: serine 3-dehydrogenase (NADP+) EC 1.1.1.277: 3β-hydroxy-5β-steroid dehydrogenase EC 1.1.1.278: 3β-hydroxy-5α-steroid dehydrogenase EC 1.1.1.279: (R)-3-hydroxyacid-ester dehydrogenase EC 1.1.1.280: (S)-3-hydroxyacid-ester dehydrogenase EC 1.1.1.281: GDP-4-dehydro-6-deoxy-D-mannose reductase EC 1.1.1.282: Quinate/shikimate dehydrogenase EC 1.1.1.283: methylglyoxal reductase (NADPH-dependent) EC 1.1.1.284: S-(hydroxymethyl)glutathione dehydrogenase EC 1.1.1.285: 3′′-deamino-3′′-oxonicotianamine reductase EC 1.1.1.286: isocitrate—homoisocitrate dehydrogenase EC 1.1.1.287: D-arabinitol dehydrogenase (NADP+) EC 1.1.1.288: xanthoxin dehydrogenase EC 1.1.1.289: sorbose reductase EC 1.1.1.290: 4-phosphoerythronate dehydrogenase EC 1.1.1.291: 2-hydroxymethylglutarate dehydrogenase EC 1.1.1.292: 1,5-anhydro-D-fructose reductase (1,5-anhydro-D-mannitol-forming) EC 1.1.1.293: tropinone reductase I. This enzyme was already in the Enzyme List as EC 1.1.1.206, tropine dehydrogenase so EC 1.1.1.293 has been withdrawn at the public-review stage EC 1.1.1.294: chlorophyll(ide) b reductase EC 1.1.1.295: momilactone-A synthase EC 1.1.1.296: dihydrocarveol dehydrogenase EC 1.1.1.297: limonene-1,2-diol dehydrogenase EC 1.1.1.298: 3-hydroxypropionate dehydrogenase (NADP+) EC 1.1.1.299: malate dehydrogenase [NAD(P)+)] EC 1.1.1.300: NADP-retinol dehydrogenase EC 1.1.1.301: D-arabitol-phosphate dehydrogenase EC 1.1.1.302: 2,5-diamino-6-(ribosylamino)-4(3H)-pyrimidinone 5′-phosphate reductase EC 1.1.1.303: Diacetyl reductase ((R)-acetoin forming) EC 1.1.1.304: Diacetyl reductase ((S)-acetoin forming) EC 1.1.1.305: UDP-glucuronic acid dehydrogenase (UDP-4-keto-hexauronic acid decarboxylating) EC 1.1.1.306: S-(hydroxymethyl)mycothiol dehydrogenase EC 1.1.1.307: D-xylose reductase EC 1.1.1.308: sulfopropanediol 3-dehydrogenase EC 1.1.1.309: phosphonoacetaldehyde reductase (NADH) EC 1.1.1.310: (S)-sulfolactate dehydrogenase EC 1.1.1.311: (S)-1-phenylethanol dehydrogenase EC 1.1.1.312: 2-hydroxy-4-carboxymuconate semialdehyde hemiacetal dehydrogenase EC 1.1.1.313: sulfoacetaldehyde reductase EC 1.1.1.314: Now known to be catalyzed by EC 1.14.14.95, germacrene A hydroxylase EC 1.1.1.315: 11-cis-retinol dehydrogenase EC 1.1.1.316: L-galactose 1-dehydrogenase EC 1.1.1.317: perakine reductase EC 1.1.1.318: eugenol synthase EC 1.1.1.319: isoeugenol synthase EC 1.1.1.320: benzil reductase [(S)-benzoin forming] EC 1.1.1.321: benzil reductase [(R)-benzoin forming] EC 1.1.1.322: (–)-endo-fenchol dehydrogenase EC 1.1.1.323: (+)-thujan-3-ol dehydrogenase EC 1.1.1.324: 8-hydroxygeraniol dehydrogenase EC 1.1.1.325: sepiapterin reductase (L-threo-7,8-dihydrobiopterin forming) EC 1.1.1.326: zerumbone synthase EC 1.1.1.327: 5-exo-hydroxycamphor dehydrogenase EC 1.1.1.328: nicotine blue oxidoreductase EC 1.1.1.329: 2-deoxy-scyllo-inosamine dehydrogenase EC 1.1.1.330: very-long-chain 3-oxoacyl-CoA reductase EC 1.1.1.331: secoisolariciresinol dehydrogenase EC 1.1.1.332: chanoclavine-I dehydrogenase EC 1.1.1.333: decaprenylphospho-β-D-erythro-pentofuranosid-2-ulose 2-reductase EC 1.1.1.334: methylecgonone reductase EC 1.1.1.335: UDP-N-acetyl-2-amino-2-deoxyglucuronate dehydrogenase EC 1.1.1.336: UDP-N-acetyl-D-mannosamine dehydrogenase EC 1.1.1.337: L-2-hydroxycarboxylate dehydrogenase (NAD+) EC 1.1.1.338: (2R)-3-sulfolactate dehydrogenase (NADP+) EC 1.1.1.339: dTDP-6-deoxy-L-talose 4-dehydrogenase (NAD+) EC 1.1.1.340: 1-deoxy-11β-hydroxypentalenate dehydrogenase EC 1.1.1.341: CDP-abequose synthase EC 1.1.1.342: CDP-paratose synthase EC 1.1.1.343: phosphogluconate dehydrogenase (NAD+-dependent, decarboxylating) EC 1.1.1.344: dTDP-6-deoxy-L-talose 4-dehydrogenase [NAD(P)+] EC 1.1.1.345: D-2-hydroxyacid dehydrogenase (NAD+) EC 1.1.1.346: 2,5-didehydrogluconate reductase (2-dehydro-L-gulonate-forming) EC 1.1.1.347: geraniol dehydrogenase (NAD+) EC 1.1.1.348: (3R)-2′-hydroxyisoflavanone reductase EC 1.1.1.349: norsolorinic acid ketoreductase EC 1.1.1.350: ureidoglycolate dehydrogenase (NAD+) EC 1.1.1.351: phosphogluconate dehydrogenase [NAD(P)+-dependent, decarboxylating] EC 1.1.1.352: 5′-hydroxyaverantin dehydrogenase EC 1.1.1.353: versiconal hemiacetal acetate reductase EC 1.1.1.354: farnesol dehydrogenase (NAD+) EC 1.1.1.355: 2′-dehydrokanamycin reductase EC 1.1.1.356: GDP-L-colitose synthase EC 1.1.1.357: 3α-hydroxysteroid 3-dehydrogenase EC 1.1.1.358: 2-dehydropantolactone reductase EC 1.1.1.359: aldose 1-dehydrogenase [NAD(P)+] EC 1.1.1.360: glucose/galactose 1-dehydrogenase EC 1.1.1.361: glucose-6-phosphate 3-dehydrogenase EC 1.1.1.362: aklaviketone reductase EC 1.1.1.363: glucose-6-phosphate dehydrogenase [NAD(P)+] EC 1.1.1.364: dTDP-4-dehydro-6-deoxy-α-D-gulose 4-ketoreductase EC 1.1.1.365: D-galacturonate reductase EC 1.1.1.366: L-idonate 5-dehydrogenase (NAD+) EC 1.1.1.367: UDP-2-acetamido-2,6-β-L-arabino-hexul-4-ose reductase EC 1.1.1.368: 6-hydroxycyclohex-1-ene-1-carbonyl-CoA dehydrogenase EC 1.1.1.369: D-chiro-inositol 1-dehydrogenase EC 1.1.1.370: scyllo-inositol 2-dehydrogenase (NAD+) EC 1.1.1.371: scyllo-inositol 2-dehydrogenase (NADP+) EC 1.1.1.372: D/L-glyceraldehyde reductase EC 1.1.1.373: sulfolactaldehyde 3-reductase EC 1.1.1.374: UDP-N-acetylglucosamine 3-dehydrogenase EC 1.1.1.375: L-2-hydroxycarboxylate dehydrogenase [NAD(P)+] EC 1.1.1.376: L-arabinose 1-dehydrogenase [NAD(P)+] EC 1.1.1.377: L-rhamnose 1-dehydrogenase (NADP+) EC 1.1.1.378: L-rhamnose 1-dehydrogenase [NAD(P)+] EC 1.1.1.379: (R)-mandelate dehydrogenase EC 1.1.1.380: L-gulonate 5-dehydrogenase EC 1.1.1.381: 3-hydroxy acid dehydrogenase EC 1.1.1.382: ketol-acid reductoisomerase (NAD+) EC 1.1.1.383: ketol-acid reductoisomerase [NAD(P)+] EC 1.1.1.384: dTDP-3,4-didehydro-2,6-dideoxy-α-D-glucose 3-reductase EC 1.1.1.385: dihydroanticapsin dehydrogenase EC 1.1.1.386: ipsdienol dehydrogenase EC 1.1.1.387: L-serine 3-dehydrogenase (NAD+) EC 1.1.1.388: glucose-6-phosphate dehydrogenase (NAD+) EC 1.1.1.389: 2-dehydro-3-deoxy-L-galactonate 5-dehydrogenase EC 1.1.1.390: sulfoquinovose 1-dehydrogenase EC 1.1.1.391: 3β-hydroxycholanate 3-dehydrogenase (NAD+) EC 1.1.1.392: 3α-hydroxycholanate dehydrogenase (NADP+) EC 1.1.1.393: 3β-hydroxycholanate 3-dehydrogenase (NADP+) EC 1.1.1.394: aurachin B dehydrogenase EC 1.1.1.395: 3α-hydroxy bile acid-CoA-ester 3-dehydrogenase EC 1.1.1.396: bacteriochlorophyllide a dehydrogenase EC 1.1.1.397: β-methylindole-3-pyruvate reductase EC 1.1.1.398: 2-glutathionyl-2-methylbut-3-en-1-ol dehydrogenase EC 1.1.1.399: 2-oxoglutarate reductase EC 1.1.1.400: 2-methyl-1,2-propanediol dehydrogenase EC 1.1.1.401: 2-dehydro-3-deoxy-L-rhamnonate dehydrogenase (NAD+) EC 1.1.1.402: D-erythritol 1-phosphate dehydrogenase EC 1.1.1.403: D-threitol dehydrogenase (NAD+) EC 1.1.1.404: tetrachlorobenzoquinone reductase EC 1.1.1.405: ribitol-5-phosphate 2-dehydrogenase (NADP+) EC 1.1.1.406: galactitol 2-dehydrogenase (L-tagatose-forming) EC 1.1.1.407: D-altritol 5-dehydrogenase EC 1.1.1.408: 4-phospho-D-threonate 3-dehydrogenase EC 1.1.1.409: 4-phospho-D-erythronate 3-dehydrogenase EC 1.1.1.410: D-erythronate 2-dehydrogenase EC 1.1.1.411: L-threonate 2-dehydrogenase EC 1.1.1.412: 2-alkyl-3-oxoalkanoate reductase EC 1.1.1.413: A-factor type γ-butyrolactone 1′-reductase (1S-forming) EC 1.1.1.414: L-galactonate 5-dehydrogenase EC 1.1.1.415: noscapine synthase EC 1.1.1.416: isopyridoxal dehydrogenase (5-pyridoxolactone-forming) EC 1.1.1.417: 3β-hydroxysteroid-4β-carboxylate 3-dehydrogenase (decarboxylating) EC 1.1.1.418: plant 3β-hydroxysteroid-4α-carboxylate 3-dehydrogenase (decarboxylating) EC 1.1.1.419: nepetalactol dehydrogenase EC 1.1.1.420: D-apiose dehydrogenase EC 1.1.1.421: D-apionate oxidoisomerase EC 1.1.1.422: pseudoephedrine dehydrogenase EC 1.1.1.423: (1R,2S)-ephedrine 1-dehydrogenase EC 1.1.1.424: D-xylose 1-dehydrogenase (NADP+, D-xylono-1,4-lactone-forming) EC 1.1.1.425: levoglucosan dehydrogenase EC 1.1.1.426: UDP-N-acetyl-α-D-quinovosamine dehydrogenase
Important musical rhythms of the Andean Region are the danza (dance of Andean folklore arising from the transformation of the European contredance), the bambuco (it is played with guitar, tiple and mandolin, the rhythm is danced by couples), the pasillo (a rhythm inspired by the Austrian waltz and the Colombian "danza", the lyrics have been composed by well-known poets), the guabina (the tiple, the bandola and the requinto are the basic instruments), the sanjuanero (it originated in Tolima and Huila Departments, the rhythm is joyful and fast). Apart from these traditional rhythms, salsa music has spread throughout the country, and the city of Cali is considered by many salsa singers to be 'The New Salsa Capital of the World'. The instruments that distinguish the music of the Eastern Plains are the harp, the cuatro (a type of four-stringed guitar) and maracas. Important rhythms of this region are the joropo (a fast rhythm and there is also tapping as a result of its flamenco ancestry) and the galeron (it is heard a lot while cowboys are working). The music of the Amazon region is strongly influenced by the indigenous religious practices. Some of the musical instruments used are the manguaré (a musical instrument of ceremonial type, consisting of a pair of large cylindrical drums), the quena (melodic instrument), the rondador, the congas, bells, and different types of flutes. The music of the Archipelago of San Andrés, Providencia and Santa Catalina is usually accompanied by a mandolin, a tub-bass, a jawbone, a guitar and maracas.
Sources: en.wikipedia.org
==== Expansion of molecular biology ==== In addition to the Division of Biology at Caltech, the Laboratory of Molecular Biology (and its precursors) at Cambridge, and a handful of other institutions, the Pasteur Institute became a major center for molecular biology research in the late 1950s. Scientists at Cambridge, led by Max Perutz and John Kendrew, focused on the rapidly developing field of structural biology, combining X-ray crystallography with Molecular modelling and the new computational possibilities of digital computing (benefiting both directly and indirectly from the military funding of science). A number of biochemists led by Frederick Sanger later joined the Cambridge lab, bringing together the study of macromolecular structure and function. At the Pasteur Institute, François Jacob and Jacques Monod followed the 1959 PaJaMo experiment with a series of publications regarding the lac operon that established the concept of gene regulation and identified what came to be known as messenger RNA. By the mid-1960s, the intellectual core of molecular biology—a model for the molecular basis of metabolism and reproduction— was largely complete. The late 1950s to the early 1970s was a period of intense research and institutional expansion for molecular biology, which had only recently become a somewhat coherent discipline. In what organismic biologist E. O. Wilson called "The Molecular Wars", the methods and practitioners of molecular biology spread rapidly, often coming to dominate departments and even entire disciplines.
=== Nucleic acids === Convergence occurs at the level of DNA and the amino acid sequences produced by translating structural genes into proteins. Studies have found convergence in amino acid sequences in echolocating bats and the dolphin; among marine mammals; between giant and red pandas; and between the thylacine and canids. Convergence has also been detected in a type of non-coding DNA, cis-regulatory elements, such as in their rates of evolution; this could indicate either positive selection or relaxed purifying selection.
Troops decapitated their bodies and displayed their heads along a public road to strike fear into those tempted to accept the Democratic Republic of Vietnam's sovereignty. Massacres did not start with the Americans in My Lai, or the Vietnamese communists in Hue in 1968. And yet, the French Union's massacre of over two hundred Vietnamese women and children in My Tratch in 1948 remains virtually unknown in France to this day. The French Army also utilized torture against Việt Minh prisoners. Benjamin Valentino estimates that the French were responsible for 60,000 to 250,000 civilian deaths.
Sources: en.wikipedia.org
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, thymine, cytosine, and guanine. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery.
Along with Blount and McClung, those who purchased lots in the city included merchants Hugh Dunlap, Thomas Humes, and Nathaniel and Samuel Cowan, newspaper publisher George Roulstone, the Reverend Samuel Carrick, frontiersman John Adair (who had built a fort just to the north in what is now Fountain City), and tavern keeper John Chisholm.
Basic diagnostic medical devices (e.g., stethoscope, tongue depressor) are typically used. After examining for signs and interviewing for symptoms, the doctor may order medical tests (e.g., blood tests), take a biopsy, or prescribe pharmaceutical drugs or other therapies. Differential diagnosis methods help to rule out conditions based on the information provided. During the encounter, properly informing the patient of all relevant facts is an important part of the relationship and the development of trust within the context of the doctor-patient relationship. The medical encounter is then documented in the medical record, which is a legal document in many jurisdictions. Follow-up encounters may be shorter but follow the same general procedure, and specialists follow a similar process. The diagnosis and treatment may take only a few minutes or a few weeks, depending on the complexity of the issue. The components of the medical interview and encounter are:
== Dosage comparison == For constant pain, the relieving effect of extended-release morphine given once (for Kadian) or twice (for MS Contin) every 24 hours is roughly the same as multiple administrations of immediate release (or "regular") morphine. Morphine sulfate pentahydrate (trade names including Dolcontin) has a higher molecular mass than morphine base, and therefore 10 mg morphine sulfate pentahydrate contains approximatively 7.5 mg of morphine free base. Extended-release morphine can be administered together with "rescue doses" of immediate-release morphine pro re nata in case of breakthrough pain, each generally consisting of 5% to 15% of the 24-hour extended-release dosage.
Sources: en.wikipedia.org
They are derived from collagen-rich animal tissues, commonly bovine hide, porcine skin, fish skin, or eggshell membrane. Processing removes non-collagen proteins and breaks the collagen into smaller water-soluble fragments. The final ingredient is a mixture, not a single peptide.
Native collagen has a triple-helical structure and is largely insoluble in cold water. Hydrolysis disrupts that structure and shortens the chains, producing peptides that dissolve more readily. The two materials also differ in molecular weight and functional behavior in foods.
They are not considered complete proteins because they are low in or lack certain essential amino acids, including tryptophan. They can still contribute amino acids when eaten with other protein sources. Labels usually list protein content rather than a complete amino acid score.
Collagen peptides are short chains of amino acids made by hydrolyzing native collagen. They are water-soluble and do not form gels like gelatin.