PT  - JOURNAL ARTICLE
AU  - T W Shih
AU  - Y F Shealy
AU  - D L Hill
TI  - Enzymatic hydrolysis of retinamides.
DP  - 1988 May 01
TA  - Drug Metabolism and Disposition
PG  - 337--340
VI  - 16
IP  - 3
4099  - http://dmd.aspetjournals.org/content/16/3/337.short
4100  - http://dmd.aspetjournals.org/content/16/3/337.full
SO  - Drug Metab Dispos1988 May 01; 16
AB  - Enzymatic activity present in liver microsomes from rats slowly hydrolyzed N-(4-hydroxyphenyl)retinamide (4HPR). A product of the reaction was all-trans-retinoic acid. The reaction, which had a pH optimum greater than 8.6, was stimulated by divalent cations, particularly Mn2+. Enzyme activity was highest in liver microsomes but was also present in kidney microsomes, liver cytoplasm, and spleen cytoplasm. Of 10 possible substrates tested, the 13-cis- and all-trans-forms of N-ethylretinamide were most active. The all-trans-form of 4HPR was much more active than the 13-cis-form. Neither 13-cis- nor all-trans-retinoyl leucine was a substrate. Because no detectable [14C]all-trans-retinoic acid could be found in the livers of rats after doses of [14C]4HPR, we conclude that this enzyme is not extensively active in intact animals.