Odbourávání purinů
Tkáně
Purine metabolism
- Mainly occurs in the liver
- Can also be produced in any other tissue that contains xanthine oxidase (intestines) [9]
- Intestines
- Muscles
- Endothelium
- Kidney [12]
Vznik k. močové
- XOD can be detected by radioimmunoassay in many kinds of human tissues
- Activity in other tissues was only 1/10 to 1/1000 compared with that in liver tissue [10]
Depurination
- Produkce volných radikálů
Štěpení nukleových kyselin
- Vznikají volné nukleotidy
- Nukleotidasami se mění na nukleosidy
- šetřící dráhou
- Některé molekuly purinových basí schopné reakce s PRPP
- Mohou znovu vytvořit nukleosidmonofosfáty (AMP, GMP) [1]
- U člověka konečným produktem metabolismu purinů kyselina močová
- Originating from hypoxanthine after double enzyme catalysis by xanthine oxidase (XOD) [10]
- Vylučuje do moči [1]
Xanthine oxidoreductase
- uric acid is product of the oxidation xanthine
- Molybdoflavoprotein enzyme
- Two functionally distinct forms:
- Xanthine dehydrogenase
- Xanthine oxidase (XOD)
- Present in significant concentrations in the liver and intestines
XOD
- Catalyzes the two terminal steps of purine degradation
- Oxidation of hypoxanthine to xanthine
- Ox. xanthine to UA
- In humans concomitant production of:
- hydrogen peroxide
- Superoxide anions
Xanthine dehydrogenase and XOD inhibitors
- Allopurinol (AP)
- Febuxostat
