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Báo cáo khoa học: Analysis of the NADH-dependent retinaldehyde reductase activity of amphioxus retinol dehydrogenase enzymes enhances our understanding of the evolution of the retinol dehydrogenase family

In vertebrates, multiple microsomal retinol dehydrogenases are involved in reversible retinol⁄retinal interconversion, thereby controlling retinoid meta-bolism and retinoic acid availability. The physiologic functions of these enzymes are not, however, fully understood, as each vertebrate form has several, usually overlapping, biochemical roles. | ỊFEBS Journal Analysis of the NADH-dependent retinaldehyde reductase activity of amphioxus retinol dehydrogenase enzymes enhances our understanding of the evolution of the retinol dehydrogenase family Diana Dalfo Neus Marques and Ricard Albalat Departament de Genetica Facultat de Biologia Universitat de Barcelona Spain Keywords cephalochordates chordate evolution retinaldehyde reductases retinoic acid metabolism retinol dehydrogenases Correspondence R. Albalat Departament de Genetica Facultat de Biologia Universitat de Barcelona Av. Diagonal 645 08028 Barcelona Spain Fax 34 934034420 Tel 34 934029009 E-mail ralbalat@ub.edu Website http www.ub.edu genetica indexen.htm Received 9 March 2007 revised 4 May 2007 accepted 30 May 2007 doi 10.1111 j.1742-4658.2007.05904.x In vertebrates multiple microsomal retinol dehydrogenases are involved in reversible retinol retinal interconversion thereby controlling retinoid metabolism and retinoic acid availability. The physiologic functions of these enzymes are not however fully understood as each vertebrate form has several usually overlapping biochemical roles. Within this context amphi-oxus a group of chordates that are simpler at both the functional and genomic levels than vertebrates provides a suitable evolutionary model for comparative studies of retinol dehydrogenase enzymes. In a previous study we identified two amphioxus enzymes Branchiostoma floridae retinol dehydrogenase 1 and retinol dehydrogenase 2 both candidates to be the cephalochordate orthologs of the vertebrate retinol dehydrogenase enzymes. We have now proceeded to characterize these amphioxus enzymes. Kinetic studies have revealed that retinol dehydrogenase 1 and retinol dehydrogenase 2 are microsomal proteins that catalyze the reduction of all-trans-retinaldehyde using NADH as cofactor a remarkable combination of substrate and cofactor preferences. Moreover evolutionary analysis including the amphioxus sequences indicates that Rdh genes were extensively .