Subsite mapping of an acidic amino acid-specific endopeptidase from Streptomyces griseus, GluSGP, and protease V8.
J Biochem
; 110(6): 859-62, 1991 Dec.
Article
em En
| MEDLINE
| ID: mdl-1794975
ABSTRACT
The substrate specificities of an acidic amino acid-specific endopeptidase of Streptomyces griseus, GluSGP, and protease V8 [EC 3.4.21.19] were investigated with peptide p-nitroanilide substrates which have a Glu residue at the P1 position. GluSGP and protease V8 favored Pro and Leu residues at S2, respectively, while the S3 subsite of GluSGP preferred Phe over either Ala or Leu. The S3 subsite of protease V8 preferred Leu over either Ala or Phe. The best substrates for GluSGP and for protease V8 were Boc-Ala-Phe-Pro-Glu-pNA with a Km value of 0.41 mM (0.1 M Tris-HCl, pH 8.8) and Boc-Ala-Leu-Leu-Glu-pNA with a Km value of 0.25 mM (0.1 M phosphate, pH 7.8), respectively. The kcat/Km values for these substrates obtained with GluSGP were about one hundred to twenty thousand times larger than those obtained with protease V8. Protease V8 exhibited a single optimal pH of around 8 for the hydrolysis of Boc-Ala-Ala-Leu-Glu-pNA and Boc-Ala-Leu-Leu-Asp-pNA.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Streptomyces griseus
/
Serina Endopeptidases
Idioma:
En
Revista:
J Biochem
Ano de publicação:
1991
Tipo de documento:
Article