d-ASPARTATE OXIDASE ACTIVITY IN EXTRACTS OF MAMMALIAN CENTRAL NERVOUS TISSUE |
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| Authors: | L P Daves G A R Johnston |
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| Institution: | Department of Pharmacology, John Curtin School of Medical Research, Australian National University, Canberra, Australia |
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| Abstract: | Abstract— d -Aspartate oxidase activity has been measured in water extracts of acetone powders prepared from cat forebrain, cerebellum and spinal cord, rat brain, hog brain and sheep brain stem, and compared with that found in rabbit and cat kidney. The results suggest that the brain enzyme has very similar properties to the n-aspartate oxidase ( d -aspartate: oxygen oxidorcductase (deaminating), EC 1.4.3.1) of kidney. Crude extracts (ammonium sulphate fractions of water extracts of acetone powders) displayed little activity without added FAD. FMN could not replace FAD. With oxygen as electron acceptor, the enzyme oxidized d -aspartate much more rapidly than d -glutamate, and displayed quite high activities with N -substituted derivatives of d -aspartate as substrates. Those amino acids susceptible to oxidation by d -amino acid oxidase were not oxidized by the d -aspartate oxidase. The regional distribution of the d -aspartate oxidase activity within the CNS differed from that of d -amino acid oxidase. As has been previously observed for kidney d -aspartate oxidase activity, dicarboxylic acids competitively inhibited this enzymic activity in brain extracts, while sodium benzoate and sodium barbitone, inhibitors of d -amino acid oxidase, were without effect. |
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