Glutamic acid dehydrogenase

Glutamic acid dehydrogenase is widely distributed in microorganisms and higher plants as a catalyst in the synthesis of L-glutamic acid from a-ketoglutaric acid and free ammonia. Transaminase is contained in a wide variety of microorganisms. 

Crotonoside. Crotonoside, also caHed isoguanosine, (45) has been isolated from Croton tiglium (4). Ip administration of [2- C]crotonoside to rats results in incorporation into nucleic acids (qv). It inhibits the inducible binding sites, inhibits glutamic acid dehydrogenase, and accumulates cAMP. 

Wla. Waisman, H. A., Monder, C., and Williams, J. N., Jr., Glutamic acid dehydrogenase and glutamic oxaloacetic transaminase of blood in leukemia and cancer. Cancer Res. 16, 344-347 (1956). 

Cultures exposed at mo developmental stages for 10 days daily-in serum-free medium to chJorpyrifos, parathion, or their oxon derivatives (1 pJVf) on culture days 5-15 (immature) or 25-35 of culture (differentiated). Cells harvested immediately or after 11-day recovery. Activities of AChE, choline acetyl transferase (ChAT), glutamic acid dehydrogenase (GAD), glutamine synthetase, and CMP measured. OP effects on AChE activity compared to physostigminc. 

C10H13N5O5 283.243 Occurs in the seeds of Croton tiglium. Also isol. from the nudibranch Diaulula sandiegensis. Incorporated into mammalian nucleic acids. Stimulates cyclic AMP incorporation into brain tissue, inhibitor of inosine monophosphate pyrophosphonylase and glutamic acid dehydrogenase. Cryst. (H2O). Sol. H2O. Mp 243-245° (237-252°) dec. [a]g -71 (c, 1.1 in O.IM NaOH). Kbx 235 (e 6140) 283 (e 12700) (0.05AT HCl) (Derep). 

The NHg-group of amines and other amino acids may be transferred by transamination (C 5) to x-ketoglutaric acid. Hence most of the ammonia liberated by the degradation of amino acids and amines is formed by glutamic acid dehydrogenase. 

The enzyme systems to be considered here are those which are relatively specific for a single amino acid and which yield ammonia as a result of the primary oxidation. Only three systems have been investigated sufficiently to warrant inclusion at this time glutamic acid dehydrogenase, glycine oxidase, and D-aspartic acid oxidase. 

The oxidation of glutamic acid by glutamic acid dehydrogenase may be represented as follows ... 

With crystalline glutamic acid dehydrogenase the turnover numbers (moles of DPN reduced or of DPNH oxidized per minute per 100,000 g. of enzyme at 25°C.) were 290 and 3000 respectively. Chance and Smith have reported the following unpublished information about the crystalline enzyme of Olson and Anfinsen. The Km values for DPN and DPN.2H are of the same order (10 M) as those for glutamate and a-ketoglutarate (10 M). The equilibrium constant for the reaction... 

L-Glutamic acid dehydrogenase was discovered independently by von Euler et al. (4) and Dewan (5). Crystallization of this enzyme was achieved by Olson and Anfinsen (d) from beef liver and by Snoke (7) from chicken liver. 

Table 10.8 Enzyme activity of L-glutamic acid dehydrogenase in the presence of surfactants (from [64])...

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