Studies on the mechanism of action of 6-mercaptopurine. Interaction with copper and xanthine oxidase.
Interaction between 6-mercaptopurine, Cu2+ and the enzyme xanthine oxidase (EC 1.2.3.2.) was examined. Whereas Cu2+ was found to inhibit the enzyme, 6-mercaptopurine could protect as well as reverse the enzyme inhibition produced by the metal ion. The formation of a complex between 6-mercaptopurine and Cu2+ seems to be responsible for the observed effect. Job's [(1928) Ann. Chem. 9, 113] method has shown the composition of the complex to be 1:1. The apparent stability constant (log K value), as determined by Subhrama Rao & Raghav Rao's [(1955) J. Sci. Chem. Ind. Res. 143, 278], method is found to be 6.74. It is suggested that the formation of a stable complex between 6-mercaptopurine molecules and Cu2+ may be an additional mechanism of action of 6-mercaptopurine, particularly with reference to its anti-inflammatory properties.
D003300:Copper / Q000378:metabolism*; D046911:Macromolecular Substances; D015122:Mercaptopurine / Q000494:pharmacology*; D013053:Spectrophotometry; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D046911:Macromolecular Substances; D003300:Copper; D015122:Mercaptopurine; D014969:Xanthine Oxidase