Inhibition of guanase in vitro by various pteridine compounds.

Pteridine derivatives have been shown to interfere with xanthine and guanine metabolism in vitro. 2-Amino-4-hydroxy-6-formylpteridine (l-3) and 2-amino-4-hydroxy-6-hydroxymethylpteridine (3) have been demonstrated to be potent inhibitors of xanthine oxidase in vitro. More recently, it has been observed that crude folic acid (4) and 6-formylpteridine (5) are inhibitors of guanase in vitro. Further investigation along these lines, utilizing the four 2-amino-4-hydroxypteridine derivatives reported in this paper, serve to demonstrate that the degree and type of guanase inhibition are affected by the configuration around the 6 position of the pteridine nucleus.