dehydrogenases. The same effects obtained when e N A D + is bound to binary complexes confirm the transfer of the coenzyme to a more hydrophobic environment, but also indicate that the coenzyme is bound to ODH in an open conformation, as found in other dehydrogenases. The high degree of conformational rigidity of bound coenzyme were deduced on the one hand from the negligible temperature coeffi...

In Zea mays L., addition of glucose to the induction medium has no effect on the induction of nitrate reductase during the initial 3 hours either in root tips (0-10 mm) or mature root sections (25-35 mm). With longer times, higher levels of enzyme activity are recovered from both root segments when glucose is present in the incubation medium. The induction in root tips is saturated by 10 mm NO(...

xix Introduction 1 0.1 Genomic approaches in the study of plant evolution . . . . . . . . . . 1 0.2 Why study gene duplication? . . . . . . . . . . . . . . . . . . . . . . 2 0.3 Duplication of genes of secondary metabolism . . . . . . . . . . . . . 4 0.4 The biological role of tropinone reductases in Solanaceae . . . . . . . 5 0.5 Tropinone reductases in Brassicaceae . . . . . . . . . . . . . ....

Ethylzinc 2,6-bis(p-tolyl)benzoate converts between two forms in solution. Through NMR spectroscopic techniques and X-ray crystallography, the species in equilibrium were identified as [Zn2(ArTolCO2)2(Et)2(THF)2] (1), [Zn2(ArTolCO2)3(Et)(THF)] (2), and diethyl zinc (ArTol = 2,6-bis(p-tolyl)phenyl). The equilibrium provides a model for understanding the speciation between doubly and triply m-ter...

Ketoacyl reductases (KRs), hydroxyacyl dehydratases (HDs) and enoyl reductases (ERs) are part of the fatty acid and polyketide synthesis cycles. Their reverse reactions, catalyzed by acyl dehydrogenases (equivalent to ERs), enoyl hydratases (equivalent to HDs) and hydroxyacyl dehydrogenases (equivalent to KRs), are part of fatty acid degradation by β-oxidation. These enzymes have been classifie...

The stereospecificity of hydride removal from the 4 position of the pyridine ring of NADH by reductases from all three classes of multicomponent nonheme iron oxygenases was examined. The class I and II reductases, modules of which show significant sequence similarity with and which belong to the ferredoxin-NADP+ reductase family of flavin-dependent oxidoreductases, transferred the pro-R hydroge...