results of these studies demonstrate that the end-products of the pathway , purine nucleotides , control the activity of the enzyme that catalyzes the first reaction leading to purine nucleotide synthesis either through a direct effect of purine nucleotides on the enzyme , through an indirect effect of the change in nucleotides on pp-ribose-p synthesis , or a combination of these effects .
C0034137
purine nucleotides
C0028630
nucleotides