Pig brain aldose reductase: purification, significance of the amino acid composition, substrate specificity and mechanism.
1. Pig brain aldose reductase (ALR2, EC 1.1.1.21) has been purified from fresh tissue with a approximately 60% improvement in specific activity over an acetone-powder preparation. 2. Dead-end inhibition and alternate substrate studies rule out an iso Theorell-Chance mechanism but are compatible with an ordered bi bi mechanism where NADPH and NADP+ function as the outside reactants in the direction of xylitol formation. 3. Subtle but significant differences are shown to exist in the distribution of apolar and mixed amino acid residues between aldose and aldehyde reductases when the mean fractional area loss [Rose et al., 1985] is used as the measure of compositional relatedness.
D000449:Aldehyde Reductase / Q000302:isolation & purification* / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D007700:Kinetics; D013379:Substrate Specificity; D013401:Sugar Alcohol Dehydrogenases / Q000302:isolation & purification*; D013552:Swine
D000596:Amino Acids; D013401:Sugar Alcohol Dehydrogenases; D000449:Aldehyde Reductase