The Radiation-Sensitizing Effects of N-Ethylmaleimide and Iodoacetic Acid on a Radiation-Resistant Micrococcus

Abstract
The sulfhydryl group combining agents, N-ethylmaleimide (NEM) and iodoacetic acid (IAA), were investigated for their abilities to enhance gamma-radiation inactivation of Micrococcus radiodurans. At the nontoxic level of 100 /xM, inactivation by irradiation was accelerated with IAA, but no effect observed with NEM. The removal of oxygen did not produce any detectable changes in the action of either chemical. The accelerated radiolethal effect appears to be due to the highly reactive radiolytic products of IAA and their nonspecific reactions with various cellular constituents.