Reductases relation

Karamloo, F., et al.. (1999). Molecular cloning and characterization of a birch pollen minor allergen. Bet v 5, belonging to a family of isoflavone reductase-related proteins, J. Allergy Clin. Immunol., 104, 991-999. 

Bartels, D., Engelhardt, K., Roncarati, R., Schneider, K., Rotter, M. Salamini, F. (1991). An ABA and GA modulated gene expressed in the barley embryo encodes an aldose reductase related protein. The EMBO Journal 10, 1037-43. 

In addition to the membrane-anchored enzymes that support anaerobic respiration, bacteria express a number of functionally, and structurally, distinct nitrate reductases related by the presence of an Mo[MGD]2 containing active site. PFV has demonstrated tunnel-diode behaviour from two of these the periplasmic Rhodobacter sphaeroides NapAB and the assimilatory Synechococcus elongatus NarB. In both cases preferential binding of nitrate to the Mo , over Mo , oxidation state provides an explanation for the catalytic voltammetry and this may prove to be a conserved feature of the catalytic cycle in these enzymes. 

Guengerich, F.P. (1983). Oxidation-reduction properties of rat liver cytochromes P-450 and NADPH-cytochrome p-450 reductase related to catalysis in reconstituted systems. Biochemistry 22, 2811-2820. 

Adalbjornsson, B.V., Toogood, H.S., Fryszkowska, A., Pudney, C.R., Jowitt, T. A., Leys, D., and Scrutton, N.S. (2010) Biocatalysis with thermostable enzymes structure and properties of a thermophilic ene -reductase related to old yellow enzyme. ChemBioChem, 11, 197-207. 

In view of the well-documented inhibition of dihydrofolate reductase by aminopterin (325), methotrexate (326) and related compounds it is generally accepted that this inhibitory effect constitutes the primary metabolic action of folate analogues and results in a block in the conversion of folate and dihydrofolate (DHF) to THF and its derivatives. As a consequence of this block, tissues become deficient in the THF derivatives, and this deficiency has many consequences similar to those resulting from nutritional folate deficiency. The crucial effect, however, is a depression of thymidylate synthesis with a consequent failure in DNA synthesis and arrest of cell division that has lethal results in rapidly proliferating tissues such as intestinal mucosa and bone marrow (B-69MI21604, B-69MI21605). 

Steps 6-8 of Figure 29.5 Reduction and Dehydration The ketone carbonyl group in acetoacetyl ACP is next reduced to the alcohol /S-hydroxybutyry] ACP by yS-keto thioester reductase and NADPH, a reducing coenzyme closely related to NADH. R Stereochemistry results at the newly formed chirality center in the /3-hydroxy thioester product. (Note that the systematic name of a butyryl group is biitanoyl.)... 

An unusual reaction was been observed in the reaction of old yellow enzyme with a,(3-unsat-urated ketones. A dismutation took place under aerobic or anaerobic conditions, with the formation from cyclohex-l-keto-2-ene of the corresponding phenol and cyclohexanone, and an analogous reaction from representative cyclodec-3-keto-4-enes—putatively by hydride-ion transfer (Vaz et al. 1995). Reduction of the double bond in a,p-unsaturated ketones has been observed, and the enone reductases from Saccharomyces cerevisiae have been purified and characterized. They are able to carry out reduction of the C=C bonds in aliphatic aldehydes and ketones, and ring double bonds in cyclohexenones (Wanner and Tressel 1998). Reductions of steroid l,4-diene-3-ones can be mediated by the related old yellow enzyme and pentaerythritol tetranitrate reductase, for example, androsta-A -3,17-dione to androsta-A -3,17-dione (Vaz etal. 1995) and prednisone to pregna-A -17a, 20-diol-3,ll,20-trione (Barna et al. 2001) respectively. 

In addition to a-l-PI, there are other examples of the presence of Met(O) residues in proteins isolated from biological material. Proteins found in lens tissue are particularly susceptible to photooxidation and because of the long half-lives of these proteins, any oxidation could be especially detrimental. In this tissue, protein synthesis is localized to the outer region of the tissue and most proteins are stable for the life of the tissue - ". It is thus somewhat surprising that not only is there no Met(O) residues in the young normal human lens but even in the old normal human lens only a small amount of Met(O) residues is found . However, in the cataractous lens as much as 65% of the Met residues of the lens proteins are found in the form of Met(0) . Whether this increase in Met(O) content in these proteins is a cause or a result of the cataracts is not known. In order to determine whether the high content of Met(O) in the cataractous lens is related to a decreased activity of Met(0)-peptide reductase, the level of this enzyme was determined in normal and cataractous lenses. It can be seen from Table 9 that there are no significant differences between the levels of Met(0)-peptide reductase in normal and cataractous lenses. In spite of these results, however, it is still possible that the Met(0)-peptide... 

Dvornik, D. (1987). Animal models of diabetic complications and their relation to aldose reductase inhibition. In Aldose Reductase Inhibition (ed. D. Porte) pp. 153-219. McGraw-Hill, New York. 

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