Pyrimidine 5'-nucleotidase activity in normal and deficient human lymphoblastoid cells

Two distinct pyrimidine 5'-nucleotidases (UMPH-1 and UMPH-2) have previously been detected in human erythrocytes; UMPH-1 is deficient in a haemolytic anaemia, while UMPH-2 is unaffected. Only the erythrocyte shows pathological effects in this disorder. Here we have studied lymphoblastoid cell lines from control and UMPH-1 deficient patients to determine whether UMPH-1 can be detected in lymphoblastoid cells and whether the deficiency of UMPH-1 results in any measurable metabolic effects. Both UMPH-1 and a UMPH-2-like activity were found to be present in control lymphoblastoid cells. UMPH-1 was undetectable in the patients' cells; minor but significant changes were found in the pyrimidine nucleotide and nucleoside pools in the cells.