PURINE-NUCLEOSIDE PHOSPHORYLASE AND ADENOSINE AMINO­ HYDROLASE ACTIVITIES IN FIBROBLASTS WITH THE LESCH­

The Lesch-Nyhan syndrome is an X-linked disease (Lesch, Nyhan, 1964) characterized by a nearly total deficiency of the hypoxanthine-guanine phosphoribosyl­ transferase activity in several tissues including the fibroblasts (Seegmiller et al., 1967; Rosenbloom et ~ 1967, 1968). The de novo synthesis of purine nucleo­ tides is greatly enhanced, and the levels of hypoxan­ thine and xanthine are considerably increased (Rosen­ bloom et al., 1967; Balis et al., 1967). It has been postulated (Lee et al., 1973) that there is so~e co­ ordinate control of the activities of the enzymes participating in the purine metabolic pathway; this control is suggested to be related to the levels of the intermediate metabolites. Barankiewicz et ale (1975) have found that in the mammary glands of mice the direction of changes in hypoxanthine-guanine phosphoribosyltransferase and purine-nucleoside phos­ phorylase activities was the same for both enzymes, i.e. they both either increased or dropped at the same time. Therefore, it was of interest to determine whether the activities of purine-nucleoside phosphory­ lase and adenosine aminohydrolase in the fibroblasts lacking hypoxanthine-guanine phosphoribosyltransferase are altered.