The peptide hydrolase system of Lactobacillus reuteri

G.ROLLÁN AND G.FONT DE VALDEZ

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

Elsevier Science Ltd

Año: 2001 vol. 70 p. 303 - 307

0168-1605

Peptide hydrolase system of Lactobacillus reuteri CRL 1098, a lactic acid bacteria of sourdough origin was determined, characterized and localized. This microorganism has a broad range of peptidases consisting of an active aminopeptidase, X-Prolyl-dipeptidylaminopeptidase, dipeptidase, and tripeptidase but scarce endopeptidase activity. Aminopeptidase, iminopeptidase and endopeptidase are most likely located in the cytoplasmic fraction showing no detectable association with the cell membrane while dipeptidase and tripeptidase are mainly associated with the last fraction. The peptidases are metalloenzymes activated by Co2+ and inhibited by Cu2+, Hg2+, Cd2+ and by metal-complexing reagents. Aminopeptidase activity inhibited by EDTA can be restored by Mn2+ while that of di- and tripeptidase treated with 1,10-phenantroline by Zn2+ and Co2+ .