JV-Acetyltransferases

JV-Acetyltransferases (NATs) catalyze the conjugation of an acetyl group from acetyl-CoA on to an amine, hydrazine or hydroxylamine moiety of an aromatic compound. NATs are involved in a variety of phase II-diug metabolizing processes. There are two isozymes NAT I and NAT II, which possess different substrate specificity profiles. The genes encoding NAT I and NAT II are both multi-allelic. Especially for NAT II, genetic polymoiphisms have been shown to result in different phenotypes (e.g., fast and slow acetylators). 

Relling, M.V., Lin, J.S., and Ayers, G.D., Racial and gender differences in jV-acetyltransferase, xanthine oxidase, and CYP1A2 activities, Clin. Pharmacol. Ther., 52, 643-658, 1992. 

A in Fig. 13.25). This is the reaction formally catalyzed by EC 2.3.1.118 with acetyl-CoA acting as the acetyl donor the JV-hydroxy metabolites of a number of arylamines are known substrates. The same conjugates can be formed by intramolecular AT,0-acetyl transfer, when an arylhydroxamic acid (an AT-aiyl-JV-hydro y-acetamide) is substrate of, e.g., EC 2.3.1.56 (reaction 3-B). In addition, such an arylhydroxamic acid can transfer its acetyl moiety to an acetyltransferase, which can then acetylate an... 

First, desmethylphosphinothricin is JV-acetylated, then coupled with two alanine residues, and finally the phosphorus is methylated. [20] In this way, the formation of free phosphinothricin is avoided. In addition, the phosphinothricin acetyltransferase transfers an acetyl group to phosphinothricin itself, whereby this is inactivated and can no longer bind to glutamine synthase (see scheme on page 684). 

Fig. 24.1 Polyamine and glutathione metaboUc pathway differences in parasite and mammalian ceU enzymes involved in polyamine biosynthesis (purple font inside solid ovcds), catabolic enzymes black font inside dashed ovals), and enzymes involved in glutathione metabolism (red font inside solid ovals). ODC ornithine decarboxylase, AdoMetDC S-adenosylmethionine decarboxylase, SpdSyn spermidine synthase, SpmSyn spermine synthase, SMO spermine oxidase, SSAT spermidine/spermine N acetyltransferase, APAO JV acetyl polyamine oxidase, yGCS...

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