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Purification and partial characterization of an intracellular aminopeptidase from Streptococcus salivarius subsp. thermophilus strain ACA‐DC 114
Author(s) -
Tsakalidou Efthimia,
Kalantzopoulos G.
Publication year - 1992
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.1365-2672.1992.tb01828.x
Subject(s) - aminopeptidase , streptococcus salivarius , enzyme , biochemistry , sephadex , chemistry , streptococcus thermophilus , hydrolysis , enzyme assay , strain (injury) , endopeptidase , chromatography , biology , streptococcus , amino acid , bacteria , leucine , lactobacillus , fermentation , anatomy , genetics
E. TSAKALIDOU AND G. KALANTZOPOULOS. 1992. An intracellular aminopeptidase from Streptococcus salivarius subsp. thermophilus strain ACA‐DC 114, isolated from traditional Greek yoghurt, was purified by chromatography on DEAE‐cellulose and Sephadex G‐100. The enzyme had a molecular weight of 89 000. It was active over a pH range 4.5‐9.5 and had optimum activity on L‐lysyl‐4‐nitroanilide at pH 6.5 and 35°C with K m = 1.80 mmol/l; above 55°C the enzyme activity declined rapidly. The aminopeptidase was capable of degrading substrates by hydrolysis of the N ‐terminal amino acid; it had very low endopeptidase and no carboxypeptidase activity. The enzyme was strongly inactivated by EDTA. Serine and sulphydryl group reagents had no effect on enzyme activity.