Effect of solvents on rat liver cytosolic acetyl CoA:arylamine N-acetyltransferase activity in vitro.

The effect of several solvents on the in vitro activity of rat liver N-acetyltransferase (NAT) isozymes was examined. Dimethylsulfoxide (DMSO), dimethylformamide, dimethyl-acetamide, ethanol, and methanol all reduced NAT II activity in concentrations ranging from 1.25 to 10%. DMSO caused a similar magnitude of reduction in NAT I and NAT II activity. The inhibitory activity of DMSO was characterized as competitive in nature. These results indicate that solvents frequently used to solubilize arylamines may have significant inhibitory activity towards NAT in vitro.