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Comparison of bovine β-casein hydrolysis by PI and PIII-type proteinases from Lactobacillus lactis subsp. cremoris
- Source :
- Applied Microbiology and Biotechnology; December 1991, Vol. 36 Issue: 3 p344-351, 8p
- Publication Year :
- 1991
-
Abstract
- The action of the cell-wall-associated proteinases from Lactococcus lactis subsp. cremoris strains H2 and SK112 on bovine ß-casein was compared. The proteinase from the H2 strain was characterised as a P<subscript>I</subscript>-type proteinase since it did not hydrolyse a<subscript>s1</subscript>-casein and the initial trifluoroacetic acid-soluble products of ß-casein hydrolysis were identical to those previously identified as hydrolysis products of P<subscript>I</subscript>-type lactococcal proteinase action. The time-course of product formation by the proteinase from the H2 strain indicated that the bonds Tyr<subscript>193</subscript>-Gln<subscript>194</subscript> and Gln<subscript>182</subscript>-Arg<subscript>183</subscript> were the first to be hydrolysed. Cleavage of the bonds Gln<subscript>175</subscript>-Lys<subscript>176</subscript>, Ser<subscript>168</subscript>-Lys<subscript>169</subscript>, Ser<subscript>166</subscript>-Gln<subscript>167</subscript> and Leu<subscript>163</subscript>-Ser<subscript>164</subscript> was also very rapid. Four of the five bonds in ß-casein most susceptible to hydrolysis by the P<subscript>III</subscript>-type proteinase from strain SK112 were different from those cleaved by the P<subscript>I</subscript>-type proteinase, initial hydrolysis being at the sites Tyr<subscript>193</subscript>-Gln<subscript>194</subscript>, Leu<subscript>192</subscript>-Tyr<subscript>193</subscript>, Asp<subscript>43</subscript>-Glu<subscript>44</subscript>, Gln<subscript>46</subscript>-Asp<subscript>47</subscript> and Phe<subscript>52</subscript>-Ala<subscript>53</subscript>. Early hydrolysis at the three sites in the N-terminal region of ß-casein, leading to cleavage of the N-terminal phosphopeptide and rapid precipitation of the residual fragment, represents a marked contrast to the action of P<subscript>I</subscript>-type proteinases where cleavage at sites in the N-terminal region occurs only very slowly.
Details
- Language :
- English
- ISSN :
- 01757598 and 14320614
- Volume :
- 36
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Applied Microbiology and Biotechnology
- Publication Type :
- Periodical
- Accession number :
- ejs15713037
- Full Text :
- https://doi.org/10.1007/BF00208154