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Glutamate dehydrogenase regulation

Maestri, E., Restivo, F. M., Gulli, M., and Tassi, F., 1991, Glutamate-dehydrogenase regulation in callus-cultures of Nicotiana plumbaginifolia - effect of glucose feeding and carbon source starvation on the isoenzymatic pattern, Plant Cell Environ., 14 613-618. [Pg.224]

Fig. 1. Integrated scheme showing the metabolic systems of regulation operating in eu-ryhaline Crustacea (after ref. 9). Broken lines indicate an inhibitory action of the effector and the heavy lines indicate activation. Notice the key role played by glutamic dehydrogenase as well as the controls exerted on the reactions utilizing reducing equivalents. The cAMP concentration is higher in concentrated medium than in dilute medium. The hormone responsible for this effect is not yet identified. HMPS, hexoses monophosphate shunt. Fig. 1. Integrated scheme showing the metabolic systems of regulation operating in eu-ryhaline Crustacea (after ref. 9). Broken lines indicate an inhibitory action of the effector and the heavy lines indicate activation. Notice the key role played by glutamic dehydrogenase as well as the controls exerted on the reactions utilizing reducing equivalents. The cAMP concentration is higher in concentrated medium than in dilute medium. The hormone responsible for this effect is not yet identified. HMPS, hexoses monophosphate shunt.
The glutamate produced by transamination is oxidatively deaminated by glutamate dehydrogenase to produce ammonia. This enzyme is unusual in being able to use either NAD+ or NADP+, and is subject to allosteric regulation. GTP and ATP are allosteric inhibitors, whereas GDP and ADP are allosteric activators. [Pg.373]

The major enzyme involved in the formation of ammonia in the liver, brain, muscle, and kidney is glutamate dehydrogenase, which catalyzes the reaction in which ammonia is condensed with 2-oxoglutarate to form glutamate (Sec. 15.1). Small amounts of ammonia are produced from important amine metabolites such as epinephrine, norepinephrine, and histamine via amine oxidase reactions. It is also produced in the degradation of purines and pyrimidines (Sec. 15.6) and in the small intestine from the hydrolysis of glutamine. The concentration of ammonia is regulated within narrow limits the upper limit of normal in the blood in humans is 70/tmol L-1. It is toxic to most cells at quite low concentrations hence there are specific chemical mechanisms for its removal. The reasons for ammonia toxicity are still not understood. The activity of the urea cycle in the liver maintains the concentration of ammonia in peripheral blood at 20/ molL. ... [Pg.434]

Plaitakis, A., Zaganas, I. (2001). Regulation of human glutamate dehydrogenases implications for glutamate, ammonia and energy metabolism in brain. J. Neurosci. Res. 66 899-908. [Pg.196]

Florencio, F. J., Marques, S., and Candau, P. (1987). Identification and characterization of a glutamate dehydrogenase in the unicellular cyanobacterium Synechocystis PCC 6803. FEBS Lett. 223, 37-41. Flores, E., and Herrero, A. (1994). Assimmilatory nitrogen metabolism and its regulation. In The Molecular Biology of Cyanobacteria (Bryant, D. A., ed.). Kluwer Academic, Dordrect, The Netherlands, pp. 487-517. [Pg.1433]

Melo-Oliveira, R., Oliveira, I. C., and Comzzi, G. M. (1996). Arabidopsis mutant analysis and gene regulation define a nonredundant role for glutamate dehydrogenase in nitrogen assimilation. Proc. Natl. Acad. Sci. U.S.A. 93, 4718-4723. [Pg.1437]

Fahieh, L. A., Kmiotek, E. H., Woldegiorgis, G-, Evenson, M Shrago, E and Marshall, M. (1985). Regulation of aminotransferase-glutamate dehydrogenase interactions by carbarn yl phosphate synthase, f. Mg plus kuclnc versus citrate and malate. /. Bhi. Chetn. 260, 6069-6079. [Pg.844]

The precise role of CO2 fixation in the economy of the parasite remains uncertain (see Scheibel, 1988), but the up-regulation of PEPCK in the early stages of sexual development in P. falciparum has been suggested to be important during parasite transition to the mosquito vector (Hayward, 2000). Another possibility is that CO2 fixation supplies aspartate for pyrimidine biosynthesis as well as NADPH (via glutamate dehydrogenase) and NAD (via malic dehydrogenase). [Pg.94]

Drillien, R., Aigle, M., and Lacroute, F. (1973). Yeast mutants pleiotropically impaired in the regulation of the two glutamate dehydrogenases. Biochem. Biophys. Res. Commun. 53, 367-372. [Pg.331]

It is noteworthy that glutamate synthase occurs in a complex with glutamate dehydrogenase in E. coli (4 ). The two activities can be copurified 30-fold. An important mechanism of regulation may be provided by association of the two enzymes in vivo. [Pg.299]

With respect to amino acid metabolism some of the differences between host and parasite are somewhat subtle. Some parasite enzymes, for example, have properties which are clearly distinct from those of their mammalian counterparts, such as the cofactor dependence and regulation of glutamate dehydrogenases. The utilization of specific amino acids such as proline or the accumulation of others such as alanine reflects a difference in the relative importance of the pathways between parasite and host. Some differences are particularly striking, especially among anaerobic protozoa in... [Pg.83]


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See also in sourсe #XX -- [ Pg.360 , Pg.361 , Pg.362 , Pg.363 , Pg.364 , Pg.365 , Pg.443 ]

See also in sourсe #XX -- [ Pg.360 , Pg.361 , Pg.362 , Pg.363 , Pg.364 , Pg.365 , Pg.443 ]




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