The modification of the cytotoxic effect of leucocidin by N-Ethylmaleimide, Flavine Mononucleotide and Menadione

Abstract

The movement of the cyto-plasmic granules in the leukocidin-treated leukocyte is prevented in the presence of N-ethylmaleimide or menadione. This effect follows a change of state in the cytoplasm. It may not be due to reaction with SH groups. When granule movement is prevented in this way the subsequent addition of Ca2+ and adenosine triphosphate (ATP) does not induce the secretion of the proteins of the granules. Menadione or iodoacetate stimulates some effects of suboptimum amounts of leukocidin. This effect probably follows a reaction with SH groups. Flavine mononucleotide inhibits some effects of suboptimum amounts of leukocidin. Leukocidin decreases the stimulation of glucose oxidation due to menadione but increases that due to flavine mononucleotide. Leukocidin decreases the adsorption of menadione by leukocytes but increases that of flavine mononucleotide. The redox state of the nicotinamide-adenine nucleotide coenzymes is not altered during leukocidin action and flavine mononucleotide and menadione do not undergo significant continuous oxidation and reduction when added to the leukocyte.