Superoxide dismutase in extracellular fluids

Abstract

Serum from healthy volunteers contained very little CuZn superoxide dismutase. Larger amounts were found in serum from patients with impaired renal function, and there was a good correlation between serum creatinine and serum CuZn superoxide dismutase content. Almost all superoxide dismutase activity of human serum was cyanide sensitive, and was found to be given by a factor(s) with a molecular mass of approximately 130000. The factor was found in all human extracellular fluids investigated: plasma, serum, lymph, ascites and cerebrospinal fluid. The factor was not recognized by radioimmunoassay for human CuZn superoxide dismutase, and it was not inhibited by rabbit antibodies against human CuZn superoxide dismutase. A similar high-molecular mass factor was found in plasma from all mammals investigated: horse, cow, pig, dog, cat, rabbit, rat and mouse. The activities differed much among species and were mostly higher than those found in human serum/plasma.