Extraction and Partial Characterization of Proteolytic Activities from the Cell Surface of Lactobacillus helveticus Zuc2

Abstract

Proteolytic activities were extracted from a dairy Lactobacillus helveticus strain and partially characterized. A first cell envelope proteinase (CEP) was extracted using a high ionic strength buffer, both in the presence and in the absence of Ca2+. Moreover, cell treatment by 5 M LiCl allowed for the selective removal of the S-layer protein and CEP, suggesting an enzyme ionic linkage to the cell envelope similar to that observed for the Slayer structure. The enzyme specificity against alpha(s1)-CN (f1-23) showed unusual activity on the Lys3-His4 bond compared with other proteinases of the same species. A second proteinase appeared to be linked to the cell membrane because it was extractable only after membrane disgregation by detergents. Its specificity against CN fractions and alpha(s1)-CN (f1-23) was different from that of the first CEP; moreover, the measured activity was lower than that of CEP.

Simultaneous Presence of PrtH and PrtH2 Proteinases in Lactobacillus helveticus Strains Improves Breakdown of the Pure α s1 -Casein

“…The absence of hydrolysis was not observed in previous studies, likely because the ␣ s1 -casein peptide f(1-23), on which both CEPs are active and have at least three common cleavage sites, was used as a marker of specificity (32,34,36,42) rather than native whole ␣ s1 -casein as in this study. Interestingly, the proteinase of Lactobacillus delbrueckii subsp.…”

“…L. helveticus strains are therefore capable of generating a diverse range of interesting textural or bioactive properties in dairy products (4,11,33). Despite the multiple technological applications of L. helveticus, little is known regarding the activity and specificity of its CEPs (23,24,26,42,45,46).…”

Comparative analysis of β-casein proteolysis by PrtP proteinase from Lactobacillus paracasei subsp. paracasei BGHN14, PrtR proteinase from Lactobacillus rhamnosus BGT10 and PrtH proteinase from Lactobacillus helveticus BGRA43

“…Furthermore, among the lactobacilli strains, the highest diversity of proteinases characterized so far was observed also for Lb. helveticus proteinases (Genay et al, 2009;Hébert, Raya, & de Giori, 1999;Pederson et al, 1999;Scolari, Vescovo, Zacconi, & Vescovi, 2006).…”

Characterization of the Pattern of α s1 - and β-Casein Breakdown and Release of a Bioactive Peptide by a Cell Envelope Proteinase from Lactobacillus delbrueckii subsp. lactis CRL 581

“…CEPs of thermophilic lactobacilli have been isolated and characterized, mainly from Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus helveticus (8,27,34,37). The genes encoding proteinases from L. delbrueckii subsp.…”