[Purine nucleotide synthesis in human liver an its influence by benzbromarone (author's transl)].

5-Phosphoribosyl-1-pyrophosphate amidotransferase and the hypoxanthine-guanine phosphoribosyltransferases (H-PRT, A-PRT) were assayed in human liver cells and some of the properties of these enzymes were determined. The Michaelis-Menten constants of both H-PRT and A-PRT for phosphoribosylpyrophosphate are at least an order of magnitude lower than for human PP-ribose-P amidotransferase. At the enzyme level the higher specific activities of phosphoribosyltransferases would, in effect, give precedence to purine salvage in human liver. In addition, no effect of benzbromaronum on enzyme activities could be demonstrated.