Enzyme | Biologic Role | Clinical Relevance | Replication | Location in Text |
---|---|---|---|---|
CYP1A1 | CYP1A1 metabolizes | Association with habitual caffeine consumption | Yes | IV.A.4 |
– caffeine to paraxanthine, theobromine and 1,3,7-TMU | ||||
– polycyclic aromatic hydrocarbons, which are important constituents of coffee | ||||
CYP1A2 | Major enzyme involved in liver caffeine metabolism | Association with habitual caffeine consumption | Yes | IV.A.1 |
IV.A.4 | ||||
CYP2A6 | Metabolism of paraxanthine to 1,7-DMU | No clear link with consumption shown yet | Yes | IV.A.1 |
NAT2 | Metabolism of paraxanthine to AFMU | No clear link with consumption shown yet | Yes | IV.A.2 |
XO | Metabolism of 1-MX to 1-MU | 1MU:1MX ratio used following caffeine administration as a pharmacodynamic measure of drug effect on XO activity | Yes | IV.A.3 |
AFMU, 5-acetylamino-6-formylamino-3-methyluracil; CYP, cytochrome P450 followed by the number corresponding to each specific isoform; NAT2, N-acetyltransferase-2; XO, xanthine oxidase; 1,3,7-TMU, 1,3,7-trimethyluric acid; 1,7-DMU, 1,7-dimethyluric acid; 1-MX, 1-methylxanthine; 1-MU, 1-methyluric acid.