Elastin peptides from hydrolysis

By the careful hydrolysis of certain proteins, peptids of definite structure have been obtained. From silk-fibroin have been obtained the anhydrides of glycyl-d-alanine and glycyl-Z-tyrosine, and a tetrapeptid which consists of two molecules of glycine, one molecule of alanine, and one molecule of tyrosine. It has been shown that the products of the partial hydrolysis of elastin contain cZ-alanyl-Z-leucine, alanyl-proline anhydride, and glycyl-valine anhydride. Other peptids have been obtained from gliadin and casein. 

It is not always possible to apply enzymatic hydrolysis directly to proteins as they are in the native form. Native, globular proteins (e.g., from soy, corn, almond) or fibrous insoluble proteins (e.g., collagen, keratins, elastin) are generally resistant to proteolysis this is generally explained by the compact tertiary structure of the protein that protects most of the peptide bonds. In the denatured, unfolded form the peptide bonds are exposed and available for enzymatic cleavage. As native proteins in aqueous solution are in dynamic equilibrium with a number of more or less distorted forms, part of which can be considered denatured and thereby accessible to enzyme attack, the initial break of a few peptide bonds can destabilize the protein molecule and cause irreversible unfolding in some cases (e.g., hydrolysis of egg albumin by pepsin) this mechanism allows the protease to perform the hydrolysis to a remarkable extent. More frequently, especially when covalent bonds (disulfide bonds) stabilize the native form of the protein, a preliminary partial or extended denaturation is needed to make enzymatic hydrolysis possible this is normally achieved by heating or chemical attack, or a combination of the two. 

Lombard C, Bouchu D, Wallach J, Saulnier J (2005) Proteinase 3 hydrolysis of peptides derived from human elastin exon 24. Amino Acids 28 403 08... 

Enzymes usually have names that end in -ase. There are some exceptions, primarily for some of the first enzymes that were recognized, for example, trypsin, chymotrypsin, papain, and elastin. These are enzymes that catalyze the hydrolysis of peptide bonds of proteins. The more systematic naming of enzymes can be divided into three parts (1) the name of the substrate on which the enzyme acts is indicated (2) the type of reaction that is catalyzed is indicated and (3) the biological source of the enzyme (such as a particular animal or species of bacteria or plant and/or a particular organ or secretion fluid, for example, pancreas, liver, heart, saliva, etc.) is given. This third category is used when enzymes from different biological sources act on the same substrate and catalyze the same reaction but have different rates, optimum temperature or pH, and/or produce different kinds of products. 

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