Production of Protein Hydrolysates Using Enzymes
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Traditionally, protein hydrolysates for amino acid analysis are produced by hydrolysis in 6N HCl. However, this method has the disadvantage that tryptophan is totally destroyed, serine and threonine partially (5–10%) destroyed, and most importantly, asparagine and glutamine are hydrolyzed to the corresponding acids. Digestion of the protein/peptide with enzymes to produce protein hydrolysate overcomes these problems, and is particularly useful when the concentration of asparagine and glutamine is required. For peptides less than about 35 residues in size, complete digestion can be achieved by digestion with aminopeptidase M and prolidase. For larger polypeptides and proteins, an initial digestion with the nonspecific protease Pronase is required, followed by treatment with aminopeptidase M and prolidase. Since it is important that all enzymes have maximum activity, the following sections will discuss the general characteristics of these enzymes.
KeywordsAmino Acid Analysis Leucine Aminopeptidase Guanidinium Chloride Ammonium Bicarbonate Buffer Large Polypeptide
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