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The specificity of the S1' subsite of papain.

ABSTRACT: The specificity of the S(1)' subsite of the proteolytic enzyme papain was investigated by studying the effect of l-alpha-amino acid amides on the enzyme-catalysed hydrolysis of N-benzyloxycarbonylglycine p-nitrophenyl ester and by determining the kinetic parameters for the enzyme-catalysed hydrolysis of some N-benzyloxycarbonylglycyl-l-amino acid amides. These studies showed that the S(1)' subsite has a predilection for hydrophobic residues, in particular l-leucine and l-tryptophan. The specificity for these residues is manifest in both the binding and acylation steps. N-Benzyloxycarbonylglycine amide is not hydrolysed under comparable conditions, indicating that the amide group adjacent to and on the C-terminal side of the peptide bond about to be cleaved makes an important contribution to the rate of the papain-catalysed hydrolysis of peptides.

SUBMITTER: Alecio MR

PROVIDER: S-EPMC1168104 | biostudies-other | 1974 Aug

REPOSITORIES: biostudies-other

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Two cap residues in the S1 subsite of a Plasmodium falciparum M1-family aminopeptidase promote broad specificity and enhance catalysis.

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