Separation of 5'-nucleotide phosphodiesterase isoenzymes of human serum by anion exchange high pressure liquid chromatography.

5'-Nucleotide phosphodiesterase isoenzymes (5'-NPD; E.C. 3.1.4.1) of human serum were separated by anion exchange high pressure liquid chromatography. In sera of healthy donors five activities could be separated, designated as Z, A, B, C and D. Under certain pathological conditions a further isozyme E occurred. With the exception of Z all isoenzymes could be related to the activities first described by Tsou and coworkers in normal sera (Tsou et al. J Histochem Cytochem 1973; 21: 402). These authors identified by means of native gel electrophoresis the isoenzymes 5'-NPD-I, 5'-NPD-II, 5'-NPD-III and 5'-NPD-IV, designated in the reverse order of their electrophoretic mobility. By using this gel technique we characterized the activities A, B, C and D as 5'-NPD-II, -III, -IV, and -I, respectively. Activity E corresponded to an isozyme which did not migrate into the gel (designated as 5'-NPD-O).