Premium
PURIFICATION AND PROPERTIES OF TRYPSIN‐LIKE ENZYMES AND A CARBOXYPEPTIDASE A FROM EUPHAUSIA SUPERBA
Author(s) -
CHEN CHINGSAN,
YAN TSONGRONG,
CHEN HERYUAN
Publication year - 1978
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1978.tb00627.x
Subject(s) - chemistry , sephadex , carboxypeptidase , trypsin , chromatography , kunitz sti protease inhibitor , enzyme , protease , size exclusion chromatography , ammonium sulfate precipitation , carboxypeptidase a , biochemistry , chymotrypsin
Five proteases designated as A 1, A 2, B, C and D were isolated from Euphausia superba by the succesive steps of ammonium sulfate fractionation, acetone precipitation, gel filtration and DEAE‐Sephadex A‐50 chromatography, A 1, B, C and D were purified to homogeneity in disc gel electrophoresis by means of rechromatography on the DEAE‐Sephadex A‐50 column. Studies on substrate specificity of these enzymes revealed that A 2, B, C and D were trypsin‐like enzymes and A 1 a carboxypeptidase A. A 1, B, C and D had molecular weights of about 24,000, 24,000 28,000 and 27,000; optimal pH at 9.0, 8.0, 7.5 and 7.5–8. 0; and optimal temperature at 48, 50, 55–60 and 55°C, respectively. The activity of B, C and D were not inhibited by sulfhydryl reagents and N‐α‐tosyl‐L‐phenylalanylchloro‐methyl ketone, but inhibited by reducing agents, N‐α‐tosyl‐L‐lysylchloromethyl ketone and soybean trypsin inhibitor. The activity of protease A 1 was stimulated 3.5 fold by cobalt, but inhibited by 3‐indolepropionate and D‐phenylalanine.