Inactivation of rhodanese from human gastric mucosa and stomach adenocarcinoma by 2,4, 6-trinitrobenzenesulphonate and by 4,4'-diisothiocyanatostilbene-2,2'-disulphonate.
Rhodanese (thiosulphate sulphurtransferase, EC 2.8.1.1) was partially purified from normal human gastric mucosa and from gastric adenocarcinoma by DEAE-cellulose column chromatography. Rhodanese inactivation by 2, 4, 6-trinitrobenzenesulphonate and by 4,4'-diisothiocynatostilbene-2-2'-disulphonate was studied by an analysis of the time-dependence of rhodanese activity loss. Rhodanese inactivation by 2, 4, 6-trinitrobenzenesulphonate was, under all conditions tested, found to be first-order with regard to enzyme residual activity. In contrast to this, rhodanese inactivation by 4, 4'-diisothiocyanatostilbene-2, 2'-disulphonate was found to be biphasic, when log residual enzyme activity was plotted vs reaction time. The first-order rate constant, k, for rhodanese inactivation by 2, 4, 6-trinitrobenzenesulphonate was, at all pH values tested, higher with the gastric adenocarcinoma enzyme than with the normal mucosa enzyme: at pH 8.00, k is 27.0 per hour, for the normal mucosa enzyme, while for the adenocarcinoma enzyme k is 69.0 per hour. In contrast to this, no difference in the inactivation profile of the normal mucosa enzyme and the gastric adenocarcinoma enzyme was to be observed with 4,4'-diisothiocyanatostilbene-2,2'-disulphonate.
Malliopoulou
V A
VA
Department of Biological Chemistry, University of Athens Medical School, Greece.
Rakitzis
E T
ET
Malliopoulou
T B
TB
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology*; D000230:Adenocarcinoma / Q000201:enzymology*; D002848:Chromatography, DEAE-Cellulose; D005753:Gastric Mucosa / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D009578:Nitrobenzenes / Q000494:pharmacology*; D012016:Reference Values; D013267:Stilbenes / Q000494:pharmacology*; D013274:Stomach Neoplasms / Q000201:enzymology*; D013466:Sulfurtransferases / Q000037:antagonists & inhibitors*; D013884:Thiosulfate Sulfurtransferase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D014302:Trinitrobenzenesulfonic Acid / Q000494:pharmacology*
D009578:Nitrobenzenes; D013267:Stilbenes; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D014302:Trinitrobenzenesulfonic Acid; D013466:Sulfurtransferases; D013884:Thiosulfate Sulfurtransferase; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid