Etude comparative de l'action des métalloprotéases de Penicillium caseicolum et Penicillium roqueforti sur les caséines alpha s₁ et bêta

Abstract

Mots clésMétalloprotéase -Penicillium caseicolum -Penici1lium roquejorti -Hydrolyse des caséines -Focalisation isoélectrique -Electrophorèse bidimensionnelle. Titre abrégéHydrolyse des caséines par les métalloprotéases de Penicillium. Summary COMPARATIVE STUDY OF THE ACTION OF METALLOPROTEINASES OF PENICILLIUM CASEICOLUM AND PENICILLIUM ROQUEFORT! ON USl-ANDB-CASEINSWe have studied and compared in vitro action of the metalloproteinases of Penicillium caseicolum and Penicillium roqueforti on purified MÉMOIRES ORIGINAUX 235Us, and [3-caseins using electrophoresis, isoelectric focusing and 2-dimensional electrophoresis. The digestion patterns observed after migration showed that these proteinases cleaved numerous peptide bonds on both caseins. From a qualitative point of view these metalloproteinases acted in a similar way on <l.S1 and [3-caseins, however, the catalytic efficiency with which sorne peptide bonds were hydrolyzed appeared to be different from an enzyme to the other. Three peptide bonds cleaved by the metalloproteinase of P. caseicolum in [3-casein were identified: these were Lysa-Lys»; Pr09O""Glu91 and GlulOo-AlalOl.