Thus there are reports of Arabidopsis cDNA or genomic sequences corresponding to 12 of the 14 steps involved in
de novo purine nucleotide synthesis depicted in Figure 1; genes coding for formyl glycine amidine ribonucleotide
(FGAM) synthetase; (EC 6.3.5.3; PUR4) and GMP synthetase (EC 6.3.4.1; PUR14) have yet to be isolated.
Of the genes that have been isolated, relatively few have been characterized in detail.
The identification of mutants of these genes will provide insight into their roles in plant growth and the relationship of purine metabolism and other biochemical pathways