Proteolytic systems in lactic acid bacteria

Abstract

The proteolytic systems of lactic acid bacteria are important as a means of making protein and peptide N available for growth and as part of the curing or maturation processes which give foods their characteristic rheological and organoleptic properties. The proteolytic systems of lactic acid bacteria are described in relation to their growth and their functions in protein-rich foods. Their role in the manufacture of milk products is discussed.

Proline-Specific Peptidases of Lactobacillus casei Subspecies

“…Study on the regulatory mechanism of proteinases in lactococci revealed that the presence of amine acids or peptides at high extracellular concentration may prevent proteinase synthesis (Law and Koistand, 1983). However, synthesis of the cell-wall proteinases appears to be regulated by amino acids or peptides at the level of rnRNA translation.…”

“…An indirect method, which involves cell fractionation using lysozyme or Iysin (Exterkate, 1976b;Law and Koistand, 1983;Ohmiya and Sato, 1975;Thomas el al, 1974) has always been used. Cell wall components were released in the absence of intracellular marker enzymes and proteinase activity was detected in spheroplast supernatant fractions.…”

Cloning and nucleotide sequence analysis of pepV, a carnosinase gene from Lactobacillus delbrueckii subsp. lactis DSM 7290, and partial characterization of the enzyme

“…Due to the rather low content of free essential amino acids in milk they are dependent on their proteolytic abilities to degrade milk casein. Lactobacilli possess a complex proteolytic system composed of proteinases and a variety of peptidases (Abo-Elnaga & Plapp, 1987;Law & Kolstadt, 1983;Thomas & Pritchard, 1987), which act in a cascade to hydrolyse casein to small transportable peptides and amino acids. The quality of dairy products The GenBanWEMBUDDBJ accession number for the nucleotide sequence reported in this paper is 231377.…”

Cloning, sequencing and expression of the gene encoding the cell-envelope-associated proteinase from Lactobacillus paracasei subsp. paracasei NCDO 151

“…They contribute to the flavour and texture of fermented milk products (Fox, 1989;Law & Kolstad, 1983;Thomas & Mills, 1981). Much is known about the proteolytic systems of the lactococci.…”