Isocitric dehydrogenase yeast

M Lancien, P Gadal, M Hodges. Molecular characterization of higher plant NAD-dependent isocitrate dehydrogenase evidence for a heteromeric structure by the complementation of yeast mutants. Plant J 16 325-333, 1998. 

Other forms of vanadium have been implicated in the stimulation of the plasma membrane vanadate-dependent NAD(P)H oxidation reaction. Decavanadate has been shown to be a more potent stimulator of the vanadate-dependent NADH oxidation activity than added orthovanadate [30,31], Interestingly, decavanadate reductase activity has been found to be an alternative activity of an NADP-specific isocitrate dehydrogenase [32], Diperoxovanadium derivatives have also been shown to be involved in this type of reaction [33,34], Decavanadate may play a role in the biological role of vanadium, as it is found in yeast cells growing in the presence of orthovanadate [8] and is a potent inhibitor of phosphofructokinase-1, the control step of glycolysis, and other metabolic reactions [35],... 

The enzyme has been isolated from many tissues, the best source being a heart muscle or yeast. The isocitrate dehydrogenase requires the presence of cofactors Mg2+ or Mn2+. As an allosteric enzyme, it is regulated by a number of modulators. ADP, adenosine diphosphate, is a positive modulator and therefore stimulates enzyme activity. The... 

Much has been published on the controversial subject of the control of glycolysis. The following brief summary of some of the controls responsible for the Pasteur effect in yeasts is based mainly on a review by Sols and coworkers144 (see also, Fig. 7). (i) Isocitrate dehydrogenase (NAD ) (EC 1.1.1.41), one of the controlling enzymes of the tricarboxylic acid cycle (see Fig. 5), catalyzes the reaction... 

Alkyl halides are even less reactive than acyl halides, as indicated by the compilation of reaction rates of thiolate anions with various types of alkyl halides (282). Nevertheless, potentially useful affinity labels have been synthesized with alkyl halide substituents and have been shown to specifically inactivate several enzymes, albeit slowly the low reactivity of the alkyl halides may minimize nonspecific reaction. Adenosine 5 -(2-bromoethyl)phosphate has been characterized and reported to inactivate NAD -dependent isocitrate dehydrogenase (283). The 2 - and 3 -(2-bromoethyl)-AMP labels have also been synthesized, and model reactions of the bromoethyl-AMPs with cysteine, lysine, histidine, and tyrosine have been studied (284). More recently, esters of adenosine 5 -monophosphate have been prepared with ethyl, propyl, or hexyl moieties and bromo or chloro substituents at the w position (285). Yeast alcohol dehydrogenase exhibited enhanced inactivation by the hexyl derivative, but inactivation rates of other dehydrogenases were unremarkable. Two iodopropyl derivatives of cAMP have been described, namely, 1, A -(3-iodopropyleno)adenosine 3, 5 -cyclic monophosphate and 3 -0-(2-iodo-3-hydroxypropyl)adenosine 3, 5 -cyclic monophosphate the latter inactivates cAMP phosphodiesterase from human platelets, with a pseudo-first-order rate constant of 0.147 hr" (286). 

Peroxisomes in the yeast S. cerevisiae are the only site of P-oxidation and furthermore, this yeast species is able to degrade a range of polyunsaturated fatty acids with double bonds at both even and uneven positions which requires the participation of 2,4-dienoyl-CoA reductase, an NADPH-requiring reaction. Oxidation of polyunsaturated fatty acids thus requires continued reduction of NADP to NADPH. Independent studies by ourselves (Van Roermund etal ) and others (Henke et have identified the peroxisomal isoform of NADP-linked isocitrate dehydrogenase as an essential component of such a NADP(H) redoxshuttle which requires full elucidation in the future. 

Evans, C.T. and Ratledge, C. (1985b) The role of the mitochondrial NAD isocitrate dehydrogenase in lipid accumulation by the oleaginous yeast Rhodosporidium toruloides CBS 14. Can. J. Microbiol. 31, 845-850. 

Non-specificity due to the presence of a DPN-specific and TPN-speci-fic enzyme in the same source material. It was demonstrated that in yeast two distinct isocitric dehydrogenases could be isolated, each free of the other. Both enzymes catalyze the same over-all oxidative decarboxylation, although some distinguishing features exist and will be discussed below. Even though the bakers and brewers yeast used as source material are not considered pure cultures, the fact that the activity of both enzymes was approximately equal in a variety of samples suggests that the two enzymes co-exist in the same cell. 

In yeast grown under hypoxic conditions succinate accumulates and the Krebs cycle is split in two branches, one diverging from oxaloacetate to succinate with simultaneous NAD recovery and the other one from oxaloacetate to glutamate, in which the NADP-linked isocitrate dehydrogenase produces the substrates needed for the NADP-linked glutamate dehydrogenase, namely 2-oxoglutarate and NADPH.< )... 

Morgunov, I., Solodovnikova, N.Y., Sharychev, A.A., Kamzolova, S., Finogenova, T., 2004. Regulation of NAD" "-dependent isocitrate dehydrogenase in the citrate producing yeast Yarrowia lipolytica. Biochemistry (Moscow) 69, 1391—1398. 

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