This document discusses the metabolism of purine nucleotides. It describes how purine bases are recycled through the salvage pathway using phosphoribosyl pyrophosphate (PRPP) and enzymes like adenine phosphoribosyltransferase (APRT) and hypoxanthine-guanine phosphoribosyltransferase (HGPRT). Primary gout is caused by enzyme defects while secondary gout results from overproduction or decreased excretion of uric acid. Symptoms of gout include arthritis in the big toe joint and treatment involves a low purine diet, allopurinol to inhibit xanthine oxidase, and probenecid or colchicine. Lesch-Ny

1. METABOLISM OF PURINE
NUCLEOTIDES

2. Origin of the ring atoms of purine

16. Purine bases are recycled from Salvage Path way
Adenine + PRPP AMP+ PPi
Guanine + PRPP GMP+Ppi
Hypoxanthine+ PRPP IMP+PPi
APRT
HGPRT
HGPRT

23. GOUT
Primary Gout:
Enzyme defect
Secondary Gout
1.Over production of Uric acid (Cancer, Starvation,alcohol)
2.Decreased excretion of uric acid (renal failure, Lactic
acidosis, alcohol)

24. GOUT
Symptoms:
Arthritis of Metatarsophalangeal joint
Precipatated by high purine diet & alcohol
Tophi – chronic cases
Treatment:
Decreased purine intake
Allopurinol- xanthine oxidase inhibitor
Probenacid – uricosurics
Colchicine – anti inflammatory

25. LESCH- NYHAN SYNDROME
X – linked disorder
HGPRTase deficiency
Self mutilation, mental retardation, nephrolithiasis

26. PURINE NUCLEOTIDE ANALOGS
Used as Anti cancer agents:
Mercaptopurine
Methotrexate
Azaserine
6-TG (thioguanine)
8 AG (Azaguanine)