Characterization and peptidase specificity of lugworm (Arenicola cristata) protease C.
1. Lugworm protease C further purified by benzamidine-affinity chromatography, exhibited peptidase specificity for arginyl and lysyl bonds. 2. Protease C consisted of a single polypeptide with a mol. wt of ca 23,000 as determined by SDS polyacrylamide gel electrophoresis, exhibited a u.v. absorption maximum at 280 with an (mg/ml) extinction coefficient of 0.93 and fluorescence spectra typical of a protein containing tryptophan, and had an amino acid composition similar to trypsins. 3. The Kms of the cleavages of the arginyl bond of oxidized insulin B chain and of the lysyl bond of the gly23-ala30 fragment were determined to be 0.72 and 0.96 mM; the corresponding kcats were 38 sec-1 and 1.5 sec-1. The Km and kcat for TAME were 0.042 mM, and 110 sec-1. 4. Lugworm protease C was confirmed to be a trypsin.
Lin
Y M
YM
Department of Chemistry, Tennessee State University, Nashville 37203.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002846:Chromatography, Affinity; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments; D011077:Polychaeta / Q000201:enzymology*; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity; D014357:Trypsin / Q000302:isolation & purification / Q000378:metabolism*
D000596:Amino Acids; D010446:Peptide Fragments; D014357:Trypsin