Kinetic and electrophoretic studies of human erythrocytes deficient in pyrimidine 5'-nucleotidase

The mutant enzyme of a patient with hereditary pyrimidine 5'-nucleotidase deficiency was analyzed biochemically. Partially purified by DEAE-Sephadex and concentrated by ultrafiltration, the enzyme had a high Km for the substrate uridine monophosphate. Utilization of the substrate cytidine monophosphate was normal, but utilization of adenosine monophosphate was greatly increased. The enzyme was stable to heat; the pH optimum was acidic. Electrophoresis of the enzyme revealed a very faint, slower than normal band.