Isolation, purification and partial characterization of four digestive proteases from the purple seastar Pisaster ochraceus

Autor: D. C. Williams, A. L. Farrand
Rok vydání: 1988
Předmět:
Zdroj: Marine Biology. 97:231-236
ISSN: 1432-1793
0025-3162
DOI: 10.1007/bf00391307
Popis: An investigation of enzymatic activity in the pyloric caeca of Pisaster ochraceus collected at Post Point, Bellingham, Washington, USA, in 1982, revealed the presence of four distinct proteases. These enzymes have been partially purified and characterized and display tryptic, chymotryptic and carboxypeptidase A-like activity. The two distinctive tryptic enzymes have molecular weights of 88 000 and 25 200 daltons, respectively, as determined by reducting SDS-PAGE electrophoresis. The chymotryptic and carboxypeptidase A proteases have molecular weights of 22 800 and 34 400 daltons, respectively. The tryptic and chymotryptic enzymes are inactivated by phenylmethylsulfonyl fluoride, indicating that all are serine proteases. Both trypsins are inhibited by soybean trypsin inhibitor; however, the high molecular weight trypsin was not inhibited by tosyl-L-lysine chloromethyl ketone. The chymotrypsin was inhibited by tosyl-L-phenylalanine chloromethyl ketone. Both reagents indicate the involvement of histidine in the active site. The low molecular weight trypsin and the chymotrypsin were able to activate bovine trypsinogen to trypsin, as determined in a modified PAGE electrophoresis with trypsinogen and casein copolymerized in the gel.
Databáze: OpenAIRE