Ribose-phosphate pyrophosphokinase 1 (PRPS1) (PRPS1)

Ribose-phosphate pyrophosphokinase 1 (PRPS1) is the primary enzyme responsible for generating phosphoribosyl pyrophosphate (PRPP), an essential precursor for the synthesis of purine and pyrimidine nucleotides [Source: UniProt P60891]. It functions as a central metabolic hub by converting ribose 5-phosphate and ATP into PRPP, which is then utilized in both de novo and salvage pathways [Source: PubMed 12555053]. Dysregulation of PRPS1 is linked to several clinical conditions; gain-of-function mutations lead to PRPS1 superactivity characterized by hyperuricemia and gout, while loss-of-function mutations cause neurodegenerative disorders like Arts syndrome and Charcot-Marie-Tooth disease X-linked type 5 [Source: NIH Gene 5617]. While PRPS1 is not a traditional membrane receptor, it is a critical metabolic target for allosteric feedback inhibition by nucleotide analogs. Drugs such as 6-mercaptopurine and 6-thioguanine are metabolized by pathways that consume the PRPP pool, and their active metabolites can inhibit PRPS1 to disrupt nucleotide production [Source: PubChem CID 667490]. As such, PRPS1 activity and PRPP availability are significant determinants of cellular nucleotide homeostasis and the clinical efficacy of various antimetabolite therapies.

Other names

Phosphoribosyl pyrophosphate synthetase 1PRPS1PRS-IRibose-phosphate pyrophosphokinase IPhosphoribosyl pyrophosphate precursor5-phosphoribosyl-1-pyrophosphate synthetase

Allosteric feedback inhibition by nucleotide analogs; competitive inhibition of substrate binding; depletion of the PRPP pool via consumption by alternative substrates (thiopurines) [Source: PubChem CID 667490].