Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2440948 | Journal of Dairy Science | 2006 | 10 Pages |
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 αs1-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 αs1-CN (f1-23) was different from that of the first CEP; moreover, the measured activity was lower than that of CEP.
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Authors
G. Scolari, M. Vescovo, C. Zacconi, F. Vescovi,