title: Reduction of vanadium(V) to vanadium(IV) by NADPH, and vanadium(IV) to vanadium(III) by cysteine methyl ester in the presence of biologically relevant ligands.
abstract: To better understand the mechanism of vanadium reduction in ascidians, we examined the reduction of vanadium(V) to vanadium(IV) by NADPH and the reduction of vanadium(IV) to vanadium(III) by L-cysteine methyl ester (CysME). UV-vis and electron paramagnetic resonance spectroscopic studies indicated that in the presence of several biologically relevant ligands vanadium(V) and vanadium(IV) were reduced by NADPH and CysME, respectively. Specifically, NADPH directly reduced vanadium(V) to vanadium(IV) with the assistance of ligands that have a formation constant with vanadium(IV) of greater than 7. Also, glycylhistidine and glycylaspartic acid were found to assist the reduction of vanadium(IV) to vanadium(III) by CysME.
authors.affiliation: Department of Chemistry, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan.
authors.forename: Mohammad K
authors.initials: MK
authors.lastname: Islam
authors.forename: Chieko
authors.initials: C
authors.lastname: Tsuboya
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kusaka
authors.forename: Sen-ichi
authors.initials: S
authors.lastname: Aizawa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ueki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Michibata
authors.forename: Kan
authors.initials: K
authors.lastname: Kanamori
mesh_terms: D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D008024:Ligands; D009249:NADP / Q000378:metabolism*; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D014639:Vanadium / Q000737:chemistry*
chemical_list: D004151:Dipeptides; D008024:Ligands; D014639:Vanadium; C027787:glycylhistidine; C035650:glycylaspartic acid; D009249:NADP; D003545:Cysteine; C017507:mecysteine