HPRT is a crucial enzyme in purine metabolism, functioning as a purine salvage enzyme that catalyzes the conversion of hypoxanthine and guanine into their respective mononucleotides, inosine monophosphate and guanosine monophosphate. This enzymatic activity is vital for recycling purines, which are essential building blocks for nucleic acids and energy metabolism. HPRT exists as a homotetramer and requires two magnesium ions as cofactors for activity, highlighting the importance of metal ion interactions in function. Deficiencies in HPRT can lead to severe metabolic disorders, including gout and Lesch-Nyhan syndrome, underscoring HPRT′s critical role in maintaining purine homeostasis.