title: Determination of the cleavage specificity of Streptomyces griseus protease B in the presence of guanidinium chloride.
abstract: Streptomyces griseus protease B (SGPB), a Pronase enzyme, has been shown to be stable and active in the presence of 6.0 M guanidinium chloride (Siegel, S. et al. (1972) J. Biol. Chem. 247, 4155-4159). In order to determine the cleavage specificity of this unusual enzyme under denaturing conditions, 12 peptides of known amino acid sequence were hydrolyzed by SGPB in the absence and presence of 6.0 M guanidinium chloride. The new N-terminal amino acids produced by the action of SGPB were dansylated and quantitatively identified by reverse phase HPLC. The results indicate that SGPB retained its cleavage specificity for phenylalanyl, tyrosyl, tryptophanyl, and leucyl peptide bonds in the presence of 6.0 M guanidinium chloride. Of these peptide bonds, SGPB exhibited a greater cleavage preference for phenylalanyl and tryptophanyl bonds, which was relatively unaffected by the presence of the denaturant. The SGPB-catalyzed cleavages of the leucyl peptide bonds examined (Leu-Met, Leu-Arg, Leu-Val, Leu-Thr, and Leu-Ile) were substantially decreased under denaturing conditions, while Leu-Gly bond cleavage by SGPB was virtually unaffected by denaturant. The demonstrated predictability of the catalytic preference of this unusual protease for phenylalanyl, tyrosyl, tryptophanyl, and leucyl-glycine peptide bonds under denaturing conditions enhances its utility in the site-specific proteolysis of insoluble or otherwise proteolysis-resistant polypeptide substrates.
mesh_terms: D000595:Amino Acid Sequence; D003619:Dansyl Compounds; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology*; D012697:Serine Endopeptidases / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D003619:Dansyl Compounds; D006146:Guanidines; D012697:Serine Endopeptidases; C024984:streptogrisin B; D019791:Guanidine