Biomaterial Database

Phosphate activation of glutaminase in sonicated mitochondria of normal and acidotic rat kidneys. 1976

D J O'Donovan

Glutaminase activity was assayed in homogenates and mitochondria of kidneys from normal and acidotic rats. These preparations were also subjected to ultrasonic disintegration and the enzyme was assayed in the pellets and supernatants resulting from ultracentrifugation. Glutaminase activity was recovered mainly in the mitochondrial fraction of unsonicated tissue. Sonication released some of the glutaminase from the mitochondria. The increase in glutaminase activity due to the addition of phosphate was greater for the enzyme released from the mitochondria by sonication than for the enzyme recovered in the mitochondrial pellet after centrifugation. Acidosis did not significantly alter glutaminase activity when assayed in Tris buffer. However, when phosphate was present in the incubation medium acidosis increased glutaminase activity whether or not it remained attached to the mitochondrial membrane during sonication. The data indicates that there is more than one isoenzyme of glutaminase in kidney mitochondria and that the sensitivities of these isoenzymes to phosphate are not identical.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005972	Glutaminase		Phosphate-Activated Glutaminase,Glutaminase, Phosphate-Activated,Phosphate Activated Glutaminase
D000138	Acidosis	A pathologic condition of acid accumulation or depletion of base in the body. The two main types are RESPIRATORY ACIDOSIS and metabolic acidosis, due to metabolic acid build up.	Metabolic Acidosis,Acidoses,Acidoses, Metabolic,Acidosis, Metabolic,Metabolic Acidoses
D000641	Ammonia	A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013010	Sonication	The application of high intensity ultrasound to liquids.	Sonications
D013347	Subcellular Fractions	Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)	Fraction, Subcellular,Fractions, Subcellular,Subcellular Fraction