Specificity of an extracellular proteinase from Brevibacterium linens ATCC 9174 on bovine beta-casein
1997
The specificity of the extracellular proteinase from Brevibacterium linens ATCC 9174 on bovine beta-casein was studied. Hydrolysis was monitored over time by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and urea-PAGE. The major pH 4.6-soluble peptides were isolated by high-performance liquid chromatography and identified by N-terminal amino acid sequencing and mass spectrometry. The major sites of hydrolysis were Ser-18--Ser-19, Glu-20--Glu-21, Gln-56--Ser-57, Gln-72--Asn-73, Leu-77--Thr-78, Ala-101--Met-102, Phe-119--Thr-120, Leu-139--Leu-140, Ser-142--Trp-143, His-145--Gln-146, Gln-167--Ser-168, Gln-175--Lys176, Tyr-180--Pro-181, and Phe-190--Leu-191. The proteinase had a broad specificity for the amino acid residues present at the P1 and P'1 positions but showed a preference for hydrophobic residues at the P2, P3, P4, P'2, P'3, and P'4 positions.
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