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Effect of allopurinol and its metabolic derivatives on the configuration of human orotate phosphoribosyltransferase and orotidine 5'-phosphate decarboxylase

1975; Elsevier BV; Volume: 24; Issue: 3 Linguagem: Inglês

10.1016/0006-2952(75)90221-x

1873-2968

Wolfgang Gröbner, William N. Kelley,

Signaling Pathways in Disease

The administration of allopurinol or oxipurinol leads to an apparent increase in the specific activity of orotate phosphoribosyltransferase and orotidine 5'-phosphate decarboxylase in man. In the present study, we have shown that human orotate phosphoribosyltransferase and orotidine 5'-phosphate decarboxylase exist in a complex as three different molecular species with molecular weights of 55,000, 80,000 and 113,000. The larger forms of the complex are more stable than the small form. In the presence of allopurinol ribonucleotide or oxipurinol-7-ribonucleotide, but not the free bases, allopurinol or oxipurinol, the largest, most stable species predominates. These findings lend support to the hypothesis that the increased activity of these two enzymes may be related in some manner to their stabilization. The possibility that the apparent increase in activity is due largely to stabilization of the complex during cell lysis and extraction rather than actual stabilization in vivo is most consistent with the data currently available.