Analysis of secreted protein profile and enzymatic activities from Corynebacterium diphtheriae and Bordetella pertussis on production batch media using peptide quenched fluorescent substrates

Abstract

Proteases were identified and characterized from the culture supernatant of the C. diphtheriae and B. pertussis bacteria. the proteases were secreted in the media and detected at the end of the exponential growth phase. Activity was detected in some fluorescent substrates, based on selected protein sequences such as insuline beta-chain, bradykinin, and synaptobrevin. the proteases were purified by means of gel filtration chromatography. Sodium dodecyl sulfate- polyacrylamide gel electrophoresis ( SDS- PAGE) analysis of the purified proteins indicated, for the main secreted proteins, an estimated molecular mass of 30 kDa in C. diphtheriae and 69 kDa in B. pertussis culture media. the proteases were stable and presented enzymatic activity at 378 degrees C. These proteases were not related to the main toxic compounds described in these two bacteria, but could represent good markers for the fermentation process when the enzyme activity was measured with the fluorescent substrates.