Premium
Aminopeptidase N from Streptococcus salivarius subsp. thermophilus NCDO 573: purification and properties
Author(s) -
Midwinter Robyn G.,
Pritchard G.G.
Publication year - 1994
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1994.tb03076.x
Subject(s) - tripeptide , streptococcus salivarius , aminopeptidase , biochemistry , hydrolysis , enzyme , oligopeptide , lactococcus lactis , amino acid , chemistry , residue (chemistry) , peptide bond , peptide , bacteria , stereochemistry , biology , lactic acid , streptococcus , leucine , genetics
A 96 kDa aminopeptidase was purified from Streptococcus salivarius subsp. thermophilus NCDO 573. The enzyme had similar properties to aminopeptidases isolated from lactococci and lactobacilli and showed a high degree of N ‐terminal amino acid sequence homology to aminopeptidase N from Lactococcus lactis subsp. cremoris. It catalysed the hydrolysis of a range of aminoacyl 4‐nitroanilides and 7‐amido‐4‐methylcoumarin derivatives, dipeptides, tripeptides and oligopeptides. In common with aminopeptidases from other lactic acid bacteria, the enzyme from Strep. salivarius subsp. thermophilus showed highest activity with lysyl derivatives but was also very active with arginyl and leucyl derivatives. Relative activity with alanyl, phenylalanyl, tyrosyl, seryl and valyl derivatives was considerably lower and with glycyl, glutamyl and prolyl derivatives almost negligible. The aminopeptidase also catalysed the hydrolysis of dipeptides and tripeptides but mostly at rates much less than that with L‐lysyl‐4‐nitroanilide and oligopeptides. The enzyme catalysed the successive hydrolysis of various amino acid residues from the N ‐terminus of several oligopeptides but it was unable to cleave peptide bonds on the N ‐terminal side of a proline residue.