Monkey glutathione S-aryltransferases. II. Properties of the major enzyme purified from the liver.
1. The molecular and enzymatic properties of the major component (Fraction IV) of glutathione S-aryltransferases [EC 2.5.1.13] purified from the liver of monkey (mainly rhesus monkey) have been investigated. The enzyme had a molecular weight of about 48,000 and was composed of two subunits of apparently identical molecular weight (ca. 24,000) bound to each other non-covalently. Each subunit contained one SH group. The amino acid composition showed characteristic high contents of leucine and glutamic acid residues. No amino-terminal residue was detected by the dansyl method. 2. The enzyme showed a rather broad optimum pH range from 7.5 to 9 with 1,2-dichloro-4-nitrobenzene as a substrate. It was moderately stable below 40 degrees C at pH 7.5. However, it showed an anomalous instability at pH around 4.2. It was reversibly denatured at least partially by urea or guanidine hydrochloride and irreversibly denatured by sodium dodecyl-sulfate. It was significantly inhibited by Zn2+, Cd2+, and Hg2+, and also by benzene hexachloride. It was extensively inactivated by reaction with phenylglyoxal or 2,4,6-trinitrobenzene sulfonate, whereas several SH reagents were without marked effect on the activity under the reaction conditions employed.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D004228:Dithionitrobenzoic Acid; D004355:Drug Stability; D005982:Glutathione Transferase / Q000378:metabolism; D000882:Haplorhini; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008253:Macaca mulatta; D008970:Molecular Weight; D011487:Protein Conformation; D011489:Protein Denaturation
D000596:Amino Acids; D004228:Dithionitrobenzoic Acid; D005982:Glutathione Transferase