Isolation and characterization of Perkinsus marinus proteases using bacitracin-sepharose affinity chromatography

Document Type


Publication Date



Extracellular proteases were isolated from the cell-free culture supernatant of the oyster-pathogenic protozoan, Perkinsus marinus, by bacitracin-sepharose affinity chromatography. The purified protease fractions contained >75% of the protease activity initially loaded onto the column with very high specific activity that corresponded to 8-11-fold level of protease enrichment. The isolated proteases hydrolysed a variety of protein substrates including oyster plasma. All of the isolated P. marinus proteases belonged to the serine class of proteases. Inhibitor studies involving spectrophotometric assay and gelatin gel electrophoresis showed high levels of inhibition in the presence of the serine protease inhibitors PMSF, benzamidine and chymostatin, whereas inhibitors of cysteine, aspartic, and metalloproteases showed little or no inhibition. Spectrophotometric assays involving serine-specific peptide substrates further revealed that the isolated proteases belong to the class of chymotrypsin-like serine proteases. A 41.7 kDa monomeric, N-glycosylated, serine protease (designated Perkinsin) has been identified as the major P. marinus extracellular protease. Copyright (C) 1999 Elsevier Science Inc.

Publication Source (Journal or Book title)

Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology

First Page


Last Page


This document is currently not available here.