N. Ezzat et al., CELL-WALL ASSOCIATED PEPTIDE-HYDROLASE AND ESTERASE-ACTIVITIES IN SEVERAL CHEESE-RELATED BACTERIA, Food chemistry, 48(1), 1993, pp. 19-23
Cell-wall associated proteinases, peptidases and esterases of Lactobac
illus helveticus, Pediococcus sp., Leuconostoc mesenteroides ssp. mese
nteroides, Brevibacterium linens, Propionibacterium acidipropionici an
d Bifidobacterium infantis were assayed. Proteolytic activity was meas
ured using C14-labelled casein. Aminopeptidase, dipeptidase and estera
se activities were measured using chromogenic substrates. All the chee
se related bacteria tested exhibited cell-wall proteinase activities w
ith highest being detected in Leuconostoc mesenteroides ssp. mesentero
ides, Pediococcus sp. and Brevibacterium linens. Lactobacillus helveti
cus and Brevibacterium linens exhibited greater cell-wall esterase and
aminopeptidase activities, but little of the total activities of thes
e enzymes were associated with the cell envelope. Greater properties o
f total cellular dipeptidase activities were associated with the cell
envelope, with Lactobacillus helveticus and Brevibacterium linens exhi
biting highest specific activities. The optimum pH of the crude cell-w
all proteinase of different strains ranged from pH 5.5 to 8.0 while th
e optimum temperature ranged from 20 to 40-degrees-C. The impact of pr
oteinase inhibitors tested differed between species.