Abstract
A discovery that rapid enzymic isomerization of 13-cis-retinoic acid (13-cRA) to all-trans-retinoic acid (t-RA) can be catalysed by purified hepatic glutathione S-transferases (GSTs; EC 2.5.1.18) from rat is now reported. Rates of cis-trans isomerization were determined quantitatively by HPLC. GST-catalysed reactions reached equilibrium rapidly, in marked contrast with uncatalysed or GSH-catalysed isomerizations. The GST-catalysed reaction exhibited substrate saturation kinetics with a Km of approx. 8 microM. The maximal velocity of the reaction and the catalytic efficiency of GSTs were determined. The initial rate of the reaction increased linearly as a function of enzyme concentration. Catalysis by GSTs was independent of the presence of GSH, indicating that GSTs act as GSH-independent isomerases as well as transferases. Incubation with guanidine (7-8 M) or heat-inactivation of GSTs (100 degrees C for 3 min) decreased isomerase activities by approx. 50% and 75% respectively. The same heat treatment did not significantly inhibit isomerization catalysed by GSH and apoferritin, indicating that the observed decrease in isomerase activity by heat inactivation was not primarily due to oxidation of protein thiol groups in the GSTs. The specific activity of GSTs was approx. 23- and 340-fold those of GSH and apoferritin respectively when comparisons were made on the basis of free thiol concentrations, indicating that free thiol in GSTs cannot account for the majority of observed isomerase activities and suggesting that specific conformations of GSTs are important for such activities. Complete inhibition of the reaction by low concentrations of N-ethylmaleimide (10 microM) demonstrated that intact protein thiols are required for the isomerase activities of GSTs.
Full Text
The Full Text of this article is available as a PDF (395.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chang M., Burgess J. R., Scholz R. W., Reddy C. C. The induction of specific rat liver glutathione S-transferase subunits under inadequate selenium nutrition causes an increase in prostaglandin F2 alpha formation. J Biol Chem. 1990 Apr 5;265(10):5418–5423. [PubMed] [Google Scholar]
- Chen H., Juchau M. R. Biotransformation of all-trans-retinal, 13-cis-retinal, and 9-cis-retinal catalyzed by conceptal cytosol and microsomes. Biochem Pharmacol. 1997 Mar 21;53(6):877–885. doi: 10.1016/s0006-2952(96)00879-9. [DOI] [PubMed] [Google Scholar]
- Crettaz M., Baron A., Siegenthaler G., Hunziker W. Ligand specificities of recombinant retinoic acid receptors RAR alpha and RAR beta. Biochem J. 1990 Dec 1;272(2):391–397. doi: 10.1042/bj2720391. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Habig W. H., Jakoby W. B. Assays for differentiation of glutathione S-transferases. Methods Enzymol. 1981;77:398–405. doi: 10.1016/s0076-6879(81)77053-8. [DOI] [PubMed] [Google Scholar]
- Hamm R., Hofmann K. Changes in the sulphydryl and disulphide groups in beef muscle proteins during heating. Nature. 1965 Sep 18;207(5003):1269–1271. doi: 10.1038/2071269a0. [DOI] [PubMed] [Google Scholar]
- Hayes J. D., Pulford D. J. The glutathione S-transferase supergene family: regulation of GST and the contribution of the isoenzymes to cancer chemoprotection and drug resistance. Crit Rev Biochem Mol Biol. 1995;30(6):445–600. doi: 10.3109/10409239509083491. [DOI] [PubMed] [Google Scholar]
- Johnson J. A., Finn K. A., Siegel F. L. Tissue distribution of enzymic methylation of glutathione S-transferase and its effects on catalytic activity. Methylation of glutathione S-transferase 11-11 inhibits conjugating activity towards 1-chloro-2,4-dinitrobenzene. Biochem J. 1992 Feb 15;282(Pt 1):279–289. doi: 10.1042/bj2820279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Keen J. H., Jakoby W. B. Glutathione transferases. Catalysis of nucleophilic reactions of glutathione. J Biol Chem. 1978 Aug 25;253(16):5654–5657. [PubMed] [Google Scholar]
- Kim C. I., Leo M. A., Lieber C. S. Retinol forms retinoic acid via retinal. Arch Biochem Biophys. 1992 May 1;294(2):388–393. doi: 10.1016/0003-9861(92)90700-7. [DOI] [PubMed] [Google Scholar]
- Kojima R., Fujimori T., Kiyota N., Toriya Y., Fukuda T., Ohashi T., Sato T., Yoshizawa Y., Takeyama K., Mano H. In vivo isomerization of retinoic acids. Rapid isomer exchange and gene expression. J Biol Chem. 1994 Dec 23;269(51):32700–32707. [PubMed] [Google Scholar]
- Kraft J. C., Juchau M. R. Correlations between conceptal concentrations of all-trans-retinoic acid and dysmorphogenesis after microinjections of all-trans-retinoic acid, 13-cis-retinoic acid, all-trans-retinoyl-beta-glucuronide, or retinol in cultured whole rat embryos. Drug Metab Dispos. 1992 Mar-Apr;20(2):218–225. [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]
- Levin A. A. Receptors as tools for understanding the toxicity of retinoids. Toxicol Lett. 1995 Dec;82-83:91–97. doi: 10.1016/0378-4274(95)03546-x. [DOI] [PubMed] [Google Scholar]
- Listowsky I., Abramovitz M., Homma H., Niitsu Y. Intracellular binding and transport of hormones and xenobiotics by glutathione-S-transferases. Drug Metab Rev. 1988;19(3-4):305–318. doi: 10.3109/03602538808994138. [DOI] [PubMed] [Google Scholar]
- Napoli J. L. Retinoic acid biosynthesis and metabolism. FASEB J. 1996 Jul;10(9):993–1001. doi: 10.1096/fasebj.10.9.8801182. [DOI] [PubMed] [Google Scholar]
- Petkovich M., Brand N. J., Krust A., Chambon P. A human retinoic acid receptor which belongs to the family of nuclear receptors. Nature. 1987 Dec 3;330(6147):444–450. doi: 10.1038/330444a0. [DOI] [PubMed] [Google Scholar]
- Pijnappel W. W., Hendriks H. F., Folkers G. E., van den Brink C. E., Dekker E. J., Edelenbosch C., van der Saag P. T., Durston A. J. The retinoid ligand 4-oxo-retinoic acid is a highly active modulator of positional specification. Nature. 1993 Nov 25;366(6453):340–344. doi: 10.1038/366340a0. [DOI] [PubMed] [Google Scholar]
- Shih T. W., Shealy Y. F., Strother D. L., Hill D. L. Nonenzymatic isomerization of all-trans- and 13-cis-retinoids catalyzed by sulfhydryl groups. Drug Metab Dispos. 1986 Nov-Dec;14(6):698–702. [PubMed] [Google Scholar]
- Soboll S., Gründel S., Harris J., Kolb-Bachofen V., Ketterer B., Sies H. The content of glutathione and glutathione S-transferases and the glutathione peroxidase activity in rat liver nuclei determined by a non-aqueous technique of cell fractionation. Biochem J. 1995 Nov 1;311(Pt 3):889–894. doi: 10.1042/bj3110889. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tang G. W., Russell R. M. 13-cis-retinoic acid is an endogenous compound in human serum. J Lipid Res. 1990 Feb;31(2):175–182. [PubMed] [Google Scholar]
- Thaller C., Eichele G. Isolation of 3,4-didehydroretinoic acid, a novel morphogenetic signal in the chick wing bud. Nature. 1990 Jun 28;345(6278):815–819. doi: 10.1038/345815a0. [DOI] [PubMed] [Google Scholar]
- Urbach J., Rando R. R. Isomerization of all-trans-retinoic acid to 9-cis-retinoic acid. Biochem J. 1994 Apr 15;299(Pt 2):459–465. doi: 10.1042/bj2990459. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vane F. M., Buggé C. J., Williams T. H. Metabolism of 13-cis-retinoic acid by a rat liver 9000g supernatant preparation. Drug Metab Dispos. 1982 May-Jun;10(3):212–219. [PubMed] [Google Scholar]