Enantiospecific change in products for aldose reductase-mediated reaction of glyceraldehyde with bound NADP+.
Aldose reductase-mediated reaction of glyceraldehyde with enzyme-bound NADP+ gives different products depending on the enantiomer used. D-Glyceraldehyde reacts to form a chromophore (336 nm) similar to the covalent NADP-glycolaldehyde adduct characterized previously [Grimshaw et al. (1990) Biochemistry 29, 9936-9946]. L-Glyceraldehyde, however, reacts in a slow steady-state process to form an additional chromophore whose spectral properties (lambda max 290 nm, epsilon approximately 16,700 M-1cm-1) suggest that hydration of the nicotinamide 5,6-double bond has occurred. Several mechanisms are proposed to explain this unique stereoisomer-dependent change in reaction pathway.
Grimshaw
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Lutcher Brown Department of Biochemistry, Whittier Institute for Diabetes and Endocrinology, La Jolla, CA 92037.
D000449:Aldehyde Reductase / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D005985:Glyceraldehyde / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D009249:NADP / Q000378:metabolism*; D011485:Protein Binding; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013379:Substrate Specificity
D005985:Glyceraldehyde; D009249:NADP; D000449:Aldehyde Reductase