Simultaneous presence of PrtH and PrtH2 proteinases in Lactobacillus helveticus Strains improves breakdown of the pure alphas1-casein.

ABSTRACT: Lactobacillus helveticus can possess one or two cell envelope proteinases (CEPs), called PrtH2 and PrtH. The aim of this work was to explore the diversity of 15 strains of L. helveticus, isolated from various origins, in terms of their proteolytic activities and specificities on pure caseins or on milk casein micelles. CEP activity differed 14-fold when the strains were assayed on a synthetic substrate, but no significant differences were detected between strains possessing one or two CEPs. No correlation was observed between the proteolytic activities of the strains and their rates of acidification in milk. The kinetics of hydrolysis of purified α(s1)- and β-casein by L. helveticus whole cells was monitored using Tris-Tricine sodium dodecyl sulfate (SDS) electrophoresis, and for four stra

SUBMITTER: Sadat-Mekmene L 

PROVIDER: S-EPMC3019737 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature