title: Enzymatic t-butyl hydroperoxide reduction on human erythrocyte membranes--NADPH and GSH dependent activities.
abstract: A NADPH-dependent t-butyl hydroperoxide ( TBH )-reducing activity independent of glutathione was found in addition to glutathione peroxidase activity bound to erythrocyte membranes. In "hypotonic" and "isotonic" membranes the NADPH-dependent TBH -reducing activity amounted to about 0.34 mu kat /l red blood cells (RBC) and the glutathione peroxidase activity to 0.32 mu kat /l RBC. The activities do not appear to be additive. The membrane association of the enzymes is independent of ionic strength. Under hypotonic condition about 0.2% of the total cellular catalase activity were bound to the membrane but none in "isotonic" membranes. The bound catalase appears to exhibit a glutathione dependent peroxidase activity. Membrane-bound haemoglobin exhibited a quasi- TBH -reductase activity which was inhibited by azide and cyanide.
mesh_terms: D002374:Catalase / Q000097:blood; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005978:Glutathione / Q000097:blood*; D005979:Glutathione Peroxidase / Q000097:blood; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D009249:NADP / Q000097:blood*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000097:blood*; D020122:tert-Butylhydroperoxide
chemical_list: D006454:Hemoglobins; D010545:Peroxides; D009249:NADP; D020122:tert-Butylhydroperoxide; D002374:Catalase; D005979:Glutathione Peroxidase; D005978:Glutathione