Glutamate dehydrogenase distribution

McKenna,M. C.,Stevenson,J. H.,Huang,X. etal. Differential distribution of the enzymes glutamate dehydrogenase and aspartate aminotransferase in cortical synaptic mitochondria contributes to metabolic compartmentation in cortical synaptic terminals. Neurochem. Int. 37 229-241, 2000. 

Aoki, C., Milner, T.A., Sheu, K.F., Blass, J.P., Pickel, V.M. (1987). Regional distribution of astrocytes with intense immrmoreactivity for glutamate dehydrogenase in rat brain implications for neiuon-glia interactions in glutamate transmission. J. Neurosci. 7 2214-31. 

Aoki C, Milner TA, Berger SB, Sheu K-FR, Blass JP, Pickel VM (1987a) Glial glutamate dehydrogenase ultrastructural localization and regional distribution in relation to the mitochondrial enzyme, cytochrome oxidase. 

Often there is no good clinical test available to determine the exact type of hepatic lesion, short of liver biopsy. There are certain patterns of enzyme elevation that have been identified and can be helpful (Table 38-3). ° The specificity of any serum enzyme depends on the distribution of that enzyme in the body. Alkaline phosphatase is found in the bile duct epithelium, bone, and intestinal and kidney cells. 5-Nucleotidase is more specific for hepatic disease than alkaline phosphatase, because most of the body s store of 5 -nucleotidase is in the liver. Glutamate dehydrogenase is a good indicator of centrolobular necrosis because it is found primarily in centrolobular mitochondria. Most hepatic cells have extremely high concentrations of transaminases. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are commonly measured. Because of their high concentrations and easy liberation from the hepato-cyte cytoplasm, AST and ALT are very sensitive indicators of necrotic lesions within the liver. After an acute hepatic lesion is established, it may take weeks for these concentrations to return to normal. ... 

The role of the coupled transaminase-glutamic dehydrogenase stems in amino acid nthesis has been discussed in Section IV, C. The possible role of L-amino acid oxidase in amino add syntheds has recently been proposed by Radhakrishnan and Meister ). However, the same objections raised above in relation to the low activity of this enzyme and its limited distribution must be answered before the role of this enzyme in amino acid biosyntheds can be conddered. 

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. 

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