Failure to verify high activities of polyamine oxidase in pregnancy serum

The activity of polyamine oxidase in human pregnancy serum was measured by our new specific method with radioisotopic N1-acetylspermine as substrate. The activity in pregnancy serum was very low and did not increase during gestation; it was not higher than that in nonpregnancy serum. The high polyamine oxidase activities previously reported by others appear to result from contamination with diamine oxidase, the level of which is high in pregnancy serum.