Glutaminase in neurons and astrocytes cultured from mouse brain: kinetic properties and effects of phosphate, glutamate, and ammonia

• Published in: Neurochemical research Vol. 13; no. 4; pp. 383 - 388
• Main Authors: HOGSTAD, S, SVENNEBY, G, TORGNER, I. A, KVAMME, E, HERTZ, L, SCHOUSBOE, A
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01-04-1988
• Subjects: Aging; ammonia; Ammonia - pharmacology; Animals; Animals, Newborn; Astrocytes - enzymology; Biochemistry and metabolism; Biological and medical sciences; Brain - enzymology; Brain - growth & development; Cells, Cultured; Central nervous system; Cerebellum - enzymology; Cerebral Cortex - enzymology; Fetus; Fundamental and applied biological sciences. Psychology; Glutamates - pharmacology; Glutamic Acid; Glutaminase - metabolism; Kinetics; Mice; Neurons - enzymology; Phosphates - pharmacology; Vertebrates: nervous system and sense organs; Cerebellum; Phosphates; Cell culture; Brain; Glutamic acid; Cerebral cortex; Granule neuron; Rodentia; Central nervous system; Astrocyte; Glutaminase; Ammonia; Vertebrata; Mammalia; Enzymatic activity; Mouse
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1007/bf00972489

Phosphate activated glutaminase comprises two kinetically distinguishable enzyme forms in cultures of cerebellar granule cells, of cortical neurons and of astrocytes. Specific activity of glutaminase is higher in cultured neurons compared with astrocytes. Glutaminase is activated by phosphate in all cell types investigated, however, glutaminase in astrocytes requires a much higher concentration of phosphate for half maximal activation. One of the products, glutamate, inhibits the enzyme strongly, whereas the other product ammonia has only a slight inhibitory action on the enzyme.