Effect of pH on mutagenesis by thiols in Salmonella typhimurium TA102.
The mutagenicity of thiol (SH)-containing compounds was tested in Salmonella typhimurium TA102 in the liquid preincubation method. Cysteinyl-glycine (CG), cysteine ethyl ester (CEE), L- and D-penicillamine (PA), cysteine (Cys) and glutathione (GSH) were mutagenic to strain TA102 without metabolic activation. On a molar basis, CG was the most potent mutagen. The mutagenicity of the remaining compounds decreased in the order specified above. The mutagenic response of each thiol-containing compound was a function of the pKa of the thiol group and the pH of the preincubation mixture. This indicates that a thiolate anion, rather than a free thiol, is required for mutagenesis.
Stark
A A
AA
Department of Biochemistry, Tel-Aviv University, Ramat-Aviv, Israel.
Arad
A
A
Siskindovich
S
S
Pagano
D A
DA
Zeiger
E
E
D055598:Chemical Phenomena; D002621:Chemistry; D003545:Cysteine / Q000031:analogs & derivatives / Q000633:toxicity; D004151:Dipeptides / Q000633:toxicity; D005978:Glutathione / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D009152:Mutagenicity Tests; D009153:Mutagens; D010396:Penicillamine / Q000633:toxicity; D012486:Salmonella typhimurium / Q000235:genetics*; D013438:Sulfhydryl Compounds / Q000633:toxicity*
D004151:Dipeptides; D009153:Mutagens; D013438:Sulfhydryl Compounds; C031752:ethyl cysteine; C028505:cysteinylglycine; D005978:Glutathione; D010396:Penicillamine; D003545:Cysteine