Glutamate dehydrogenase substrate specificity

See specific aminotransferase Glutamate as a substrate or product, GLUTAMATE DECARBOXYLASE GLUTAMATE DEHYDROGENASE GLUTAMATE SYNTHASE GLUTAMINE SYNTHETASE y-GLUTAMYL TRANSPEPTIDASE LEUCINE AMINOTRANSEERASE LYSINE 6-AMINOTRANSEERASE... 

Fig. 4. Specific activities (fancies substrate/minute/mg protein) of c)4 ochroine oxidase and succinate dehydrogenase of chick liver mitochondria and of malate dehydrogenase and glutamate dehydrogenase of mitochondrial matrix. Data from Greenfield and Boell (1968, 1970).

Figure 1 Enzymes as signal transdncers. As drawn, an enzyme specific for only one substrate is immobilized in close proximity to the electrode surface. The substrate (e.g., glutamate) is oxidized by the enzyme to the corresponding enzyme product (e.g., a-ketoglu-tarate) with concurrent rednction of a cofactor in a 1 1 ratio. (NAD" is rednced to NADH for dehydrogenase enzymes, and molecular oxygen is reduced to peroxide in the case of oxidase enzymes.) Of the fonr species present in solution, only the product of the cofactor reduction (NADH or H2O2) is electrochemically active and produces an analytical signal, so the enzyme substrate (glutamate in this example) is transduced to an electroactive species by the enzyme. Barring introduction of NADH (or peroxide) to the solntion, any increase in faradaic cnrrent may then be attributed to the presence of the enzyme snbstrate alone.

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