TY - JOUR
T1 - Purification and characterization of an amino tripeptidase from cytoplasm of Lactococcus lactis subsp. cremoris AM2
AU - Wilkinson, Martin
AU - Bacon, Christopher L.
AU - Vincent Jennings, P.
AU - Ni Fhaolain, Ide
AU - O'Cuinn, Gerard
PY - 1993
Y1 - 1993
N2 - An aminopeptidase was purified 120-fold with a 78% recovery from the cytoplasm of Lactococcus lactis subsp. cremoris AM2. The purified enzyme exhibited no activity on dipeptides, dipeptideamides, tripeptideamides or tetrapeptides. As activity was observed only with tripeptides, from which it released the N-terminal amino acid, the enzyme was adjudged to be a strict aminotripeptidase. The enzyme had a Mr of 105 000 and showed one band, corresponding to an Mr of 55 000 on SDS-PAGE electrophoresis. Inhibition by EDTA. 8-hydroxyquinoline and 1.10 phenanthroline indicated that the peptidase was a metallo enzyme. Dithiothreitol, bestatin and amastatin caused total inhibition, whereas p-chloromercuribenzoate, bacitracin and phenyl methyl sulphonyl fluoride were without effect. Km values for tripeptides were within the range 0·18 (Leu-Leu-Leu) to 0·38 mM (Trp-Gly-Gly). Substrate inhibition was noted with some tripeptides at concentrations above 1·5 mM.
AB - An aminopeptidase was purified 120-fold with a 78% recovery from the cytoplasm of Lactococcus lactis subsp. cremoris AM2. The purified enzyme exhibited no activity on dipeptides, dipeptideamides, tripeptideamides or tetrapeptides. As activity was observed only with tripeptides, from which it released the N-terminal amino acid, the enzyme was adjudged to be a strict aminotripeptidase. The enzyme had a Mr of 105 000 and showed one band, corresponding to an Mr of 55 000 on SDS-PAGE electrophoresis. Inhibition by EDTA. 8-hydroxyquinoline and 1.10 phenanthroline indicated that the peptidase was a metallo enzyme. Dithiothreitol, bestatin and amastatin caused total inhibition, whereas p-chloromercuribenzoate, bacitracin and phenyl methyl sulphonyl fluoride were without effect. Km values for tripeptides were within the range 0·18 (Leu-Leu-Leu) to 0·38 mM (Trp-Gly-Gly). Substrate inhibition was noted with some tripeptides at concentrations above 1·5 mM.
UR - http://www.scopus.com/inward/record.url?scp=0001697076&partnerID=8YFLogxK
U2 - 10.1016/0958-6946(93)90015-R
DO - 10.1016/0958-6946(93)90015-R
M3 - Article
AN - SCOPUS:0001697076
SN - 0958-6946
VL - 3
SP - 163
EP - 177
JO - International Dairy Journal
JF - International Dairy Journal
IS - 2
ER -