Knowra Purine metabolism Purine metabolism Purine metabolism is the cellular synthesis, recycling, and breakdown of purines, the nitrogen-containing bases adenine and guanine and their derivatives.
De novo purine biosynthesis : The pathway that builds purine nucleotides from small precursors on a ribose-phosphate scaffold. It constructs purine rings step by step, producing inosine monophosphate as the first complete nucleotide.
Purine : A nitrogen-containing bicyclic molecule that forms the structural core of adenine, guanine, and related compounds. Purine metabolism handles this shared molecular scaffold and its derivatives.
Gout : An inflammatory arthritis caused by deposition of monosodium urate crystals in joints and tissues. Excess uric acid from purine breakdown can raise urate levels and promote crystal formation.
Uric acid : The final product of purine degradation in humans, circulating mainly as urate at physiological pH. Human purine breakdown ends here because humans lack functional uricase.
Pyrimidine metabolism : The cellular synthesis, recycling, and breakdown of pyrimidine bases such as cytosine, uracil, and thymine. Its ring is assembled differently from the purine ring, which is built on ribose phosphate.
Purine salvage pathway : The pathway that recycles free purine bases into nucleotides using phosphoribosyltransferase enzymes. It reuses bases released during nucleotide breakdown, reducing the need for de novo synthesis.
Adenosine monophosphate : A nucleotide composed of adenine, ribose, and one phosphate group. It is one product of the inosine monophosphate branch and a substrate for nucleotide interconversion.
Allopurinol : A drug that inhibits xanthine oxidase and lowers uric acid production. It treats gout by reducing the terminal products of purine catabolism.
Urate : The ionized form of uric acid that predominates in blood at physiological pH. Its concentration reflects purine breakdown and influences the risk of crystal deposition.
De novo pyrimidine biosynthesis : The pathway that constructs pyrimidine nucleotides by building a ring before attaching it to ribose phosphate. This assembly order contrasts with purine synthesis, which builds the ring directly on the sugar scaffold.
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