Cell-envelope proteinase

Figure 10.22 Schematic representation of the hydrolysis of casein (a) by lactococcal cell envelope proteinase (CEP), and (b) degradation of an hypothetical dodecapeptide by the combined action of lactococcal peptidases oligopeptidase (PepO), various aminopeptidases (PCP, PepN, PepA, PepX), tripeptidase (TRP), prolidase (PRD) and dipeptidase (DIP).

Cleavage sites of cell-envelope proteinase of starter Lactococcus spp. 

Figure 10.23 Water-insoluble and water-soluble peptides derived from asl-casein (A), as2-casein (B) or -casein (C) isolated from Cheddar cheese DF = diafiltration. The principal chymosin, plasmin and lactococcal cell-envelope proteinase cleavage sites are indicated by arrows (data from T.K. Singh...

Broadbent, J.R., Barnes, M., Brennand, C., Strickland, M., Houck, K., Johnson, M.E., Steele, J.L. 2002. Contribution of Lactococcus lactis cell envelope proteinase specificity to peptide accumulation and bitterness in reduced-fat Cheddar cheese. Appl. Enviro. Micobiol. 68, 1778-1785. 

FIG. 14. Identity of peptides isolated from the water-soluble fraction of Cheddar cheese. Peptides derived from aji-casein are shown in A, those from /8-casein in B. The principal chymosin cleavage sites in Oji-casein, the principal plasmin cleavage sites in /8-casein, and the principal cleavage sites of lactococcal cell envelope proteinase on Oji- and -casein are shown by arrows (from Fox et al., 1994,1995, unpublished). 

Exterkate, F. A., and Alting, A. C. (1993). The conversion of the a,i-casein-(l-23)-fragment by the free and bound form of the cell-envelope proteinase of Lactococcus lactis subsp. cremoris under conditions prevailing in cheese. Syst. Appl. Microbiol. 16,1-8. 

Exterkate, F. A., Alting, A. C., and Bruinenberg, P. G. (1993). Diversity of cell envelop proteinase specificity among strains of Lactococcus lactis and its relationship to charge characteristics of the substrate-binding region. Appl. Environ. Microbiol. 59,3640-3647. 

Visser, S., Slangen, C. J., Robben, A. J. P. M., van Dongen, W. D., Heerma, W., and Haverkamp, J. (1994). Action of a cell-envelope proteinase (CEPm-type) from Lactococcus lactis subsp. cremoris AMI on bovine K-casein. Appl. Microbiol. Biotechnol. 41, 644-651. 

Dozens of different peptides have been identified in cheeses. Most of them arise from and -caseins and a few are from aj2-and K-caseins. The proteinases involved in hydrolysis of aj -casein are mainly cathepsin D originating from milk and cell-envelope proteinase from thermophilic starters, while P- and aj2-caseins are mainly hydrolysed by plasmin. Moreover, peptidases from starters are also active throughout the ripening process, presumably similar to those from non-starter lactic acid bacteria. For example, the bitterness of mature Gouda cheese is caused by calcium and magnesium chlorides, some bitter-tasting free amino acids and is modified by peptides, which arise from the hydrolysis of fS-casein (such as decapeptide Tyr-Pro-Phe-Pro-Gly-Pro-Ile-His-Asn-Ser and derived nonanpeptide without the terminal serine) and casein (tetrapeptide Leu-Pro-Gln-Glu). 

Figure 1.3. Diagram of the proteolytic systems of lactic acid bacteria, (a) Extracellular components PrtP, cell-envelope proteinase PrtM, proteinase maduration protein Opp, oligopetide permease DtpT, the ion linked trasnsporter for di-and tripeptides and Opt, the ABC transporter for peptides, (b) Intracelullar components pool of about 20-25 peptidases, including general (PepN, PepC) and specific (PepX, PepQ) peptidases, and amino acid catabolic enzymes (carboxylases, aminotransferases, etc.).

Hebert, E. M., Mamone, G., Picariello, et al. (2008) Characterization of the pattern of asl- and b-casein breakdown and release of a bioactive peptide by a cell envelope proteinase from Lactobacillus delbrueckii subsp. lactis CRL 581. Appl Environ Microbiol 74, 3682-3689. 

Proteases of L. bulgaricus and L. helveticus contribute to the ripening of Swiss cheese (Langsrud and Reinbold 1973). Strains of thermo-duric lactobacilli are generally more proteolytic than S. thermophilus (Dyachenko et al. 1970). The proteinase activity of L. bulgaricus is optimal at pH 5.2-5.8 and is associated with the cell envelope (Argyle et al. 1976). Some strains of L. brevis (Dacre 1953) andL. lactis (Bottazzi 1962) are also proteolytic. Surface-bound aminopeptidase from L. lactis, characterized by Eggiman and Bachman (1980), is activated by cobalt and zinc ions and has optimum activity at pH 6.2-7.2. A surface-bound proteinase and carboxypeptidase are also present in L. lactis. 

FIG. 6. Specificity of lactococcal cell envelope-associated proteinase on Osi-casein. [1] Lacto-coccus lactis spp. cremoris SKI 12 (Reid et al., 1991). [2] L. lactis ssp. lactis NCDO 763 (Monnet et al., 1992). Modified from Fox et al (1995). 

Exterkate, F. A. (1990). Differences in short peptide-substrate cleavage by two cell-envelope-located serine proteinases of Lactococcus lactis subsp. cremoris are related to secondary binding specificity. Appi. Microbiol. Biotechnol. 33, 401-406. 

Monnet, V., Ley, J. P., and Gonzalez, S. (1992). Substrate specificity of the cell envelope-located proteinase of Lactococcus lactis subsp. lactis NCDO 763. InL J. Biochem. 24,707-718. 

Reid, J. R., Coolbear, T., Pillidge, C. J., and Pritchard, G. G. (1994). Specificity of hydrolysis of bovine x-casein by cell envelope-associated proteinases from Lactococcus lactis strains. Appl. Environ. Microbiol. 60, 801-806. 

Vos, P., Simons, G., Siezen, R. J., and de Vos, W. M. (1989a). Primary structure and organization of the gene for a procaryotyc cell envelope—located serine proteinase. J. Biol. Chem. 264, 13579-13585. 

Bonifait, L., de la Cruz Dominguez-Punaro, M., VaiHancourt, K., et al. (2010) The cell envelope subtilisin-like proteinase is a virulence determinant for Streptococcus suis. BMC Microbiol 10,42. 

Espeche Turbay, M.B., de Moreno de LeBlanc, A., and Perdigon, G., et al. (2012) P-Casein hydrolysate generated by the cell envelope-associated proteinase of Lactobacillus delbrueckii ssp. lactis CRL 581 protects against trinitrobenzene sulfonic acid-induced colitis in mice. J Dairy Sci 95, 1108-1118. 

Genes for cell envelope-associated proteinases vary widely... 

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