Gelatin hydroxyproline

Animal glue is a complex colloidal mixture of proteins. The related gelatins are also complex heterogeneous mixtures of proteins. They are strongly hydrophilic and rich in the amino acids glycine, proline, lysine, hydroxyproline and hydroxylysine. Casein is a phosphoprotein obtained from the milk of mammals. 

The number of different amino acids actually found in proteins is greater than the 20 in the DNA code. This is because some of them are produced by posttranslational modification. Hydroxyproline, for example, is not coded in DNA. Proline is inserted in the peptide chain and the hydroxy group is later added to the peptidically liked proline to form hydroxyproline. Although hydroxyproline is found in some proteins that are known to be haze active, such as gelatin, polyhydroxyproline (the synthetic homopolymer of hydroxyproline) forms no haze with... 

There are many types of vertebrate collagen. Typically they contain about 35% Gly, 11% Ala, and 21% Pro and 4-Hyp (4-hydroxyproline, an uncommon amino acid see Fig. 3-8a). The food product gelatin is derived... 

L-Leucine is easily extracted in quantity from almost any type of vegetable protein hyclrolyzates. Cystine is extracted from the human-hair hyclrolyzate. L-Histidine is obtainable from the blood of animals, but future yields may stem from fermentation inasmuch as some artificial mutants of bacteria have been discovered. Gelatin is the prime source of L-hydroxyproline,... 

Gelatin is made from collagen, which is a structural protein composed primarily of glycine, proline, and hydroxyproline. As a result, gelatin has low nutritional value because it lacks many of the essential amino acids. 

Seifter et al. (1961) have also reported a fourfold increase in the proportion of neutral sugar in the nondialyzable peptides found after digestion of ichthyocol gelatin with collagenase. They do, however, still contain an appreciable amount of hydroxyproline and proline and the usual proportion of glycine, indicating that this amino acid may be uniformly distributed throughout the molecule. 

Gelatin A hydrolysis product of collagen (a natural polymer) Mostly -CO-NH- Major constituent amino acids are glycine, proline, and hydroxyproline... 

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