Abstract
Examination of the subcellular distribution of retinoic acid 5,6-epoxidase activity in rat liver and human liver homogenates showed that there is a prominent peak of activity in a high-density fraction. A corresponding peak was also detected in rat blood and human blood. Retinoic acid 5,6-epoxidation was catalysed by human blood cells but not by human plasma, and purified human haemoglobin also catalysed the epoxidation of retinoic acid to 5,6-epoxyretinoic acid. These results suggest that retinoic acid 5,6-epoxidase activity in human liver and rat liver homogenates is partially due to the presence of residual blood cells, and particularly haemoglobin, in the homogenates. In the retinoic acid 5,6-epoxidation catalysed by human haemoglobin, molecular O2 was required and its reaction was stimulated by Triton X-100. Boiling of haemoglobin solution resulted in an 94% decrease in the activity. NADPH (1 mM) and NADH (1 mM) completely [2-mercaptoethanol (5 mM) almost completely] inhibited the 5,6-epoxidation catalysed by haemoglobin, but catalase, superoxide dismutase and mannitol showed no inhibitory effect. CN- ion (100 mM) inhibited the reaction, but N3- ion (100 mM) did not.
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- Beaufay H., Amar-Costesec A., Feytmans E., Thinès-Sempoux D., Wibo M., Robbi M., Berthet J. Analytical study of microsomes and isolated subcellular membranes from rat liver. I. Biochemical methods. J Cell Biol. 1974 Apr;61(1):188–200. doi: 10.1083/jcb.61.1.188. [DOI] [PMC free article] [PubMed] [Google Scholar]
 - Dairman W., Christenson J. G. Properties of human red blood cell 1-3,4-dihydroxyphenylalanine decarboxylating activity. Eur J Pharmacol. 1973 May;22(2):135–140. doi: 10.1016/0014-2999(73)90003-4. [DOI] [PubMed] [Google Scholar]
 - Frolik C. A., Roberts A. B., Tavela T. E., Roller P. P., Newton D. L., Sporn M. B. Isolation and identification of 4-hydroxy- and 4-oxoretinoic acid. In vitro metabolites of all-trans-retinoic acid in hamster trachea and liver. Biochemistry. 1979 May 15;18(10):2092–2097. doi: 10.1021/bi00577a039. [DOI] [PubMed] [Google Scholar]
 - Frolik C. A., Tavela T. E., Newton D. L., Sporn M. B. In vitro metabolism and biological activity of all-trans-retinoic acid and its metabolites in hamster trachea. J Biol Chem. 1978 Oct 25;253(20):7319–7324. [PubMed] [Google Scholar]
 - John K. V., Lakshmanan M. R., Cama H. R. Preparation, properties and metabolism of 5,6-monoepoxyretinoic acid. Biochem J. 1967 May;103(2):539–543. doi: 10.1042/bj1030539. [DOI] [PMC free article] [PubMed] [Google Scholar]
 - Juchau M. R., Symms K. G. Aniline hydroxylation in the human placenta--mechanistic aspects. Biochem Pharmacol. 1972 Aug 1;21(15):2053–2064. doi: 10.1016/0006-2952(72)90159-1. [DOI] [PubMed] [Google Scholar]
 - LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
 - McCord J. M., Fridovich I. Superoxide dismutase. An enzymic function for erythrocuprein (hemocuprein). J Biol Chem. 1969 Nov 25;244(22):6049–6055. [PubMed] [Google Scholar]
 - McCormick A. M., Napoli J. L. Identification of 5,6-epoxyretinoic acid as an endogenous retinol metabolite. J Biol Chem. 1982 Feb 25;257(4):1730–1735. [PubMed] [Google Scholar]
 - McCormick A. M., Napoli J. L., Schnoes H. K., DeLuca H. F. Isolation and identification of 5, 6-epoxyretinoic acid: a biologically active metabolite of retinoic acid. Biochemistry. 1978 Sep 19;17(19):4085–4090. doi: 10.1021/bi00612a033. [DOI] [PubMed] [Google Scholar]
 - Mieyal J. J., Ackerman R. S., Blumer J. L., Freeman L. S. Characterization of Enzyme-like activity of human hemoglobin. Properties of the hemoglobin-P-450 reductase-coupled aniline hydroxylase system. J Biol Chem. 1976 Jun 10;251(11):3436–3441. [PubMed] [Google Scholar]
 - Mieyal J. J., Blumer J. L. Accleration of autooxidation of human oxyhemoglobin by aniline and its relation to hemoglobin-catalyzed aniline hydroxylation. J Biol Chem. 1976 Jun 10;251(11):3442–3446. [PubMed] [Google Scholar]
 - Morgan B., Thompson J. N. The preparation and biological activity of methyl 5,6-epoxy-retinoate. Biochem J. 1966 Dec;101(3):835–842. doi: 10.1042/bj1010835. [DOI] [PMC free article] [PubMed] [Google Scholar]
 - Muraoka S., Enomoto H., Sugiyama M., Yamasaki H. The mechanism of the reduction of cytochrome c by xanthine oxidase. Biochim Biophys Acta. 1967 Sep 6;143(2):408–415. doi: 10.1016/0005-2728(67)90094-1. [DOI] [PubMed] [Google Scholar]
 - Reid R., Nelson E. C., Mitchell E. D., McGregor M. L., Waller G. R., John K. V. Mass spectral analysis of eleven analogs of vitamin A. Lipids. 1973 Oct;8(10):558–565. doi: 10.1007/BF02532712. [DOI] [PubMed] [Google Scholar]
 - Roberts A. B., Nichols M. D., Newton D. L., Sporn M. B. In vitro metabolism of retinoic acid in hamster intestine and liver. J Biol Chem. 1979 Jul 25;254(14):6296–6302. [PubMed] [Google Scholar]
 - Sietsema W. K., DeLuca H. F. In vitro epoxidation of all-trans-retinoic acid in rat tissue homogenates. Biochem Biophys Res Commun. 1979 Oct 29;90(4):1091–1097. doi: 10.1016/0006-291x(79)91147-1. [DOI] [PubMed] [Google Scholar]
 - Sietsema W. K., DeLuca H. F. Retinoic acid 5,6-epoxidase. Properties and biological significance. J Biol Chem. 1982 Apr 25;257(8):4265–4270. [PubMed] [Google Scholar]
 - Symms K. G., Juchau M. R. The aniline hydroxylase and nitroreductase activities of partially purified cytochromes P-450 and P-420, and cytochrome b5 solubilized from rabbit hepatic microsomes. Drug Metab Dispos. 1974 Mar-Apr;2(2):194–201. [PubMed] [Google Scholar]
 - TAPPEL A. L. The mechanism of the oxidation of unsaturated fatty acids catalyzed by hematin compounds. Arch Biochem Biophys. 1953 Jun;44(2):378–395. doi: 10.1016/0003-9861(53)90056-3. [DOI] [PubMed] [Google Scholar]
 - Yamabe H., Lovenberg W. Decarboxylation of 3,4-dihydroxyphenylalanine by oxyhemoglobin. Biochem Biophys Res Commun. 1972 May 26;47(4):733–739. doi: 10.1016/0006-291x(72)90553-0. [DOI] [PubMed] [Google Scholar]
 
