Abstract
1.1. An inhibitor of microsomal oxidation was isolated and partially purified from the soluble fraction of house cricket (Acheta domesticus) gut contents.2.2. Inhibitory activity was greater towards armyworm gut microsomal enzymes than those from rat liver.3.3. The material was characterized as a proteolytic enzyme with a molecular weight of approximately 16,500.4.4. Proteolytic and inhibitory activity were blocked by Soy trypsin inhibitor and phenylmethanesulfonyl fluoride but not by p-chloromercuribenzoate or reduced glutathione.5.5. Inhibition apparently results from solubilization of NADPH cytochrome c reductase from the microsomal membrane.