CYP1A2 enzyme activity

DeVito MJ, Diliberto JJ, Ross DG, et al. 1997. Dose-response relationships for polyhalogenated dioxins and dibenzofurans following subchronic treatment in mice. I. CYP1A1 and CYP1A2 enzyme activity in liver, lung, and skin. Toxicol Appl Pharmacol 147 267-280. 

H. Toyoshiba, N.J. Walker, J. Bailer, and C.J. Portiera, Evaluation of toxic equivalency factors for induction of cytochromes P450 CYPlAl and CYP1A2 enzyme activity by dioxin-like compounds, Toxicol. Appl. Pharmacol. 194 (2004) 156-168. 

St John s wort 2. Royal jelly 1. Theophylline i theophylline levels and risk of therapeutic failure Due to activation of metabolizing CYP1A2 enzymes, which metabolize theophylline Discontinue St John s wort if the therapeutic effects of theophylline 4-... 

The best documented enzyme system for which decreased activity is observed in humans relates to the maturation of the CYP enzymes. In the fetal liver the CYPs 2C, lA, 2A, 2B, 3A4, 3A5, and possibly 2E are absent or present at extremely low levels, whereas CYP3A7 is actively synthesized (126,127). At birth, some of the CYP enzymes (2C, 2A, 2B, 3A4,3A5, and 2E) begin to increase in concentration for the first week, and then remain relatively constant. In contrast, the CYP1A2 enzyme seems to be expressed much later, with levels that increase during the first... 

Second, among the phase II enzyme activities such as cytochrome P450 CYP1A2, only NADPH (nicotinamide adenine dinucleotide phosphate)-quinone reductase was slightly increased by 3-methylcholanthrene (3-MC, 47), and three carotenoids of canthaxanthin (45), P-apo-8 -carotenal (25) and astaxanthin (10) except P-carotene (2). 

The synthesis of frutinone A and its derivatives was developed by Hong and Lee in 2014 via the palladium-catalyzed carbonylation of 2-phenolchro-mones [44], Remarkably, several products were applied to test the inhibitory activities of the CYP1A2 enzyme in the nanomolar range and exerted potent efficiency. 

N-demethylation at the three N-methyl sites. In this regard, the 3-N-demethylation of caffeine to generate paraxanthine can serve as a particularly good in vivo indicator of the presence and activity of CYP1A2 (Fig. 4.7). In the case of phenacetin, CYP1A2 catalyzes N-deethylation to generate acetaminophen. Not unexpectedly, 1 A2 s selectivity toward heterocyclic aromatic substrates carries over to inhibitors of the enzyme. Furafylline (Fig. 4.7) is an example of a particularly potent 1A2 mechanism-based inhibitor. 

---