Purification and characterization of a proline iminopeptidase from Propionibacterium shermanii 13673

Abstract

Summary -A proline lminopepndase activity was round in P shermanii 13673. The enzyme activity was present in the intracellular fraction. The peptidase was purifisd approximately 80 times by ionexchange chromatography on Fractogel T8K DEAE 650 and gel filtration on 8ephacryl 8-100 HR. The purified enzyme appeared as a single band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It had a molecular weight of 61 000. Optima for activity of the.purified enzyme were 40 oC and pH 8.0. The enzymatic activity was inhibited by phenylmethylsulfonylfluoride (1 mM). Divalent ions Zn, Co, Cu and Fe alsohad an inhibitor}t effect. The peptidase hydrolyzed specifically Pro p-NA amino acid, dipeptides Pro-Met, Pro-Phe, Pro-Le, Pro-lieu, Pro-G1yand 13-casomorphin des-Tyr fragment 7.

Proline-Specific Peptidases of Lactobacillus casei Subspecies

“…This result may well be compared with the broad activity of enzymes iTom the same strain (Arora and Lee, 1992;Habibi-Najafi • and Lee, 1994b) or iminopepidases ITom other strains (panon, 1990;Yoshimoto el al. 1985).…”

“…Although the amino/iminopeptidase optimally reacts at neutral pH, it also reacts and functions in the acidic environment of cheese ripening. Due to the importance offree proline in production of specifie types of cheese in particular Swiss cheese, this enzyme from secondary starters such as propionibacteria (Lagsrud et al, 1977;Panon, 1990) Casey and Meyer (1985). X-prolyl dipeptidyl peptidase (X-POP) from several Lactobacillus casei subspecies have been studied…”

“…Under high electric current, the proteins applied to the gel depend on the overal1 charge move until they reach the pH identical to their isoelectric point (pl). The isoelectric point of the pure protein was (Baankreis, 1992;Panon, 1990;Yoshimoto et al, 1983;.…”

“…The presence of proline-specific peptidases iTom starter and nonstarter lactic acid bacteria has been reported first by Casey and Meyer (1985) followed by detailed study on proline-specific peptidases of Streptococcus cremoris AM2 by Booth et al (1990a) and of Lactobacil/lls casei subspecies (Habibi-Najafi and . Several enzymes of this group iTom both starter and non-starter lactic acid bacteria have been purified to homogeneity and characterized in detail (Booth et al, 1990b;Habibi-Najafi and Lee, 1994b;Kiefer-Partsch et al, 1989;Panon, 1990).…”

“…Due to the importance of iTee proline in production of specifie type of cheese in particular Swiss cheese, this enzyme ITom secondary starters such as propionibacteria has been studied more (Lagsrud et al, 1977;Panon, 1990). …”