11 / l / l NADH - dependent Dehydroascorbate in the Rabbit Lens Reductase
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چکیده
// / The present investigation demonstrates the existence of NADH-dependent dehydroascorbate (DHA) recluctase activity in the soluble fraction of the rabbit lens. This DHA reductase was specific for NADH, and its apparent Km values for DHA and NADH were 5.7 mM and 4.0 uM, respectively. In a gel filtration of the lens soluble fraction on a Sephadex G-75 superfine column, the NADH-dependent DHA reductase activity was eluted at the oligomeric fiLl-crystallin fraction, which may also contain A-crystallin (a rabbit-specific cTystal1in). Furthemiore, about 80 % of protein fractions eparated from the fiLl-crystal1in fract on by DEAE-cellulose ion-exchange column chromatography exhibited DHA recluctase actiyity. In the SDS-PAGE analysis of the protein fractions with DHA reductase activity, 32 -33, 27 and 25 kDa protein subimits were commonly identified. These results suggest that oligomers of 6-cr ystallin andfor A-crystallin subu its may be associated with the DHA reductase activity. The present paper also discusses that the fimctien of the rechictase may be to enhance the
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