This study presents evidence for a new enzyme, d-ribose-5-P reductase, which catalyzes the reaction: d-ribose-5-P + NADPH + H(+) --> d-ribitol-5-P + NADP(+). The enzyme was isolated from Adonis vernalis L. leaves in 38% yield and was purified 71-fold. The reductase was NADPH specific and had a pH optimum in the range of 5.5 to 6.0. The Michaelis constant value for d-ribose-5-P reduction was 1.3...

We cloned and sequenced the gene encoding an NADPH-dependent aldehyde reductase (ARII) in Sporobolomyces salmonicolor AKU4429, which reduces ethyl 4-chloro-3-oxobutanoate (4-COBE) to ethyl (S)-4-chloro-3-hydroxybutanoate. The ARII gene is 1,032 bp long, is interrupted by four introns, and encodes a 37,315-Da polypeptide. The deduced amino acid sequence exhibited significant levels of similarity...

unable to bind NADPH. The results obtained so far suggest that the modified histidine residue is in, or near, the coenzyme site, and the protection by inhibitors competitive with NADPH suggest that it is in the region of the binding site for adenosine ribose and distal to the site of hydride transfer. Thiol groups. The role of thiol groups in the activity of mammalian aldehyde reductases is not...

Previously studied inhibitors of aldose reductase were largely from two chemical classes, spirosuccinamide/hydantoins and carboxylic acids. Each class has its own drawbacks regarding selectivity, in vivo potency, and human safety; as a result, the pathogenic role of aldose reductase in diabetic retinopathy remains controversial. ARI-809 is a recently discovered aldose reductase inhibitor (ARI) ...

Aldehyde oxidase (EC 1.2.3.1) has been purified by a modification of a previously reported procedure and the FAD prosthetic group has been removed by treatment with calcium chloride and calcium acetate. The deflavo enzyme so obtained is devoid of Wmethylnicotinamide oxygen reductase activity but can be reconstituted by a short incubation with FAD. The different activities of native and deflavo ...

observed in enzyme-methotrexate complexes. The orientation that appears to be required for catalysis can be readily achieved by rotations of the pteridine of 180° around the C-6-C-9 bond and 30° about the C-9-N-10 bond. In this orientation, C-4 of the NADPH nicotinamide ring closely approaches C-6 of the substrate, and N-5 of the substrate is adjacent to aspartic acid-30 of the enzyme. It has b...