GENETIC-CONTROL OF METABOLISM OF THE MUTA GENIC BASE ANALOG 6-N-HYDROXYLAMINOPURINE IN YEAST SACCHAROMYCES-CEREVISIAE

Yeasts were shown to utilize 6-substituted adenine analogues as a puri ne source via the reutilization pathway leading to the formation of in osine monophosphate (IMP). This occurs because the ade12 strains with blocked conversion of IMP into adenosine monophosphate (AMP) cannot gr ow on media containing the above analogues as a sole purine source. Ha ploid strains with the double mutation ham1ade2 or ham1ade5 were also incapable of growing on a medium with 6-N-hydroxylaminopurine (HAP) as a sole purine source. However, in this case, this inability was cause d by the occurrence of recessive lethal mutations rather than by a def ect in purine reutilization. Yeast adenine aminohydrolase (AAH) can de aminate HAP to hypoxanthine. Adenine aminohydrolase (AAH) was uniforml y active both in strains with a mutation in the HAM1 gene and in strai ns wildtype with respect to this trait.