Butyrophilin, subfamily 1, member A1.

Guanine deaminase; Catalyzes the hydrolytic deamination of guanine, producing xanthine and ammonia.

Purine nucleoside phosphorylase; The purine nucleoside phosphorylases catalyze the phosphorolytic breakdown of the N-glycosidic bond in the beta- (deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate.

Adenine phosphoribosyltransferase; Catalyzes a salvage reaction resulting in the formation of AMP, that is energically less costly than de novo synthesis.

Thiopurine S-methyltransferase; Catalyzes the S-methylation of thiopurine drugs such as 6- mercaptopurine (also called mercaptopurine, 6-MP or its brand name Purinethol) using S-adenosyl-L-methionine as the methyl donor. TPMT activity modulates the cytotoxic effects of thiopurine prodrugs. A natural substrate for this enzyme has yet to be identified.

Cytochrome P450 1A2; A cytochrome P450 monooxygenase involved in the metabolism of various endogenous substrates, including fatty acids, steroid hormones and vitamins. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (NADPH--hemoprotein reductase). Catalyzes the hydroxylation of carbon-hydrogen bonds. Exhibits high catalytic activity for the formation of hydroxyestrogens from estrone (E1) and 17beta-estradiol (E2), namely 2-hydroxy E1 and E [...]

Arylamine N-acetyltransferase 1; Participates in the detoxification of a plethora of hydrazine and arylamine drugs. Acetylates both arylamines and arylalkylamines.

Cytochrome P450 2A2; Highly active in the 15-alpha-hydroxylation of testosterone.