cDNAs specifying four active phosphoribosyl diphosphate synthase isozymes were isolated from an Arabidopsis thaliana cDNA library. In contrast to other phosphoribosyl diphosphate synthases the activity of two of the A. thaliana isozymes are independent of Pi. Amino acid sequence comparison and phylogenetic analysis indicate that these two isozymes belong to a novel class of phosphoribosyl diphosphate synthases.
Krath, B. N., Eriksen, T. A., Poulsen, T. S., & Hove-Jensen, B. (1999). Cloning and sequencing of cDNAs specifying a novel class of phosphoribosyl diphosphate synthase in Arabidopsis thaliana. Biochimica et Biophysica Acta, 1430(2), 403-408. https://doi.org/10.1016/S0167-4838(99)00022-9