Inhibition of the proteolytic contaminant in commercial xanthine oxidase preparations by serum protein fractions.
Commercial xanthine oxidase, widely used for generation of oxygen radicals in vitro, is usually contaminated by proteolytic activity, which limits its utility in studies of oxygen radical damage to protease sensitive substrates. An easily prepared fraction of fetal calf serum was found to inhibit virtually all of the proteolytic contaminant without affecting superoxide generation. The effects attainable with the "purified" enzyme were demonstrated with two protease sensitive targets: proteoglycan subunit from cartilage and fibronectin from human plasma.
D000645:Ammonium Sulfate / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D004340:Drug Contamination; D005312:Fetal Blood / Q000032:analysis* / Q000502:physiology; D005609:Free Radicals; D006801:Humans; D008722:Methods; D010100:Oxygen / Q000494:pharmacology; D010447:Peptide Hydrolases / Q000502:physiology; D011480:Protease Inhibitors / Q000037:antagonists & inhibitors*; D014969:Xanthine Oxidase / Q000494:pharmacology*
D005609:Free Radicals; D011480:Protease Inhibitors; D014969:Xanthine Oxidase; D010447:Peptide Hydrolases; D010100:Oxygen; D000645:Ammonium Sulfate