ABSTRACT
The relative molecular mass and kinetic properties of the cytosolic and mitochondrial forms of glutamate dehydrogenase from the rat heart have been reported to differ. Within liver and brain cells glutamate dehydrogenase is localized in the mitochondrial matrix and is frequently used as a marker enzyme for mitochondria in cellular fractionation studies. The equilibrium of the reaction is very much in favor of glutamate formation. Comparison of the sequences of glutamate dehydrogenases with those of other dehydrogenases for which X-ray structures are known indicates the presence of the characteristic nicotinamide-adenine dinucleotide-binding region. The enzyme is present in most mammalian tissues with the liver being the richest source. The activity per gram of tissue in the kidney cortex is about one fifth of that in the liver and relatively lower amounts of activity are present in the pancreas, brain, intestinal and gastric mucosa, heart, spleen, skeletal muscle, and lung.
