Carbocyclic substrates for de novo purine biosynthesis. Enantiospecific synthesis and enantiospecificity of enzymatic utilization.

The carbocyclic analogues of phosphoribosylamine, glycinamide ribonucleotide, and formylglycinamide ribonucleotide have been prepared enantiospecifically from D-ribonic acid gamma-lactone. These carbocycles, which have the same absolute configuration as the natural D-ribose-derived intermediates of de novo purine biosynthesis, are utilized stoichiometrically by the initial enzymes of the pathway. A comparison of the enzymatic processing of the (-)-enantiomers with those of the racemates indicates that in some cases, the (+)-enantiomer acts to inhibit the enzymatic activity.