Organ specific control of glutamine metabolism

Katunuma, Nobuhiko; Huzino, Akio; Tomino, Ikuko

doi:10.1016/0065-2571(67)90008-8

Cited by 79 publications

(34 citation statements)

References 11 publications

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“…For PIG, the assay mixture contained 10 mM glutamine, 0.2 mM EDTA, 0.02% BSA, and 60 mM Tris-HCI buffer, pH 6.0-8. 6. Glutaminase activity was determined by measuring glutamate as formazan formation spectro-photometrically at 492 nm.…”

Section: Resultsmentioning

confidence: 99%

“…Gamma GTP catalyzes the transfer of the gamma glutamyl group of glutathione to free amino acid to form the dipeptide, cysteinyl glycine and gamma-glutamyl acceptor (5). Glutaminase I has at least two isoenzymes, phosphate dependent glutaminase (PDG), requiring inorganic phosphate as an activator; and phosphate independent glutaminase (PIG), activated by maleate (6). Tate and Meister (7) have found that gamma-GTP purified from rat kidney hydrolyzed glutamine to glutamate.…”

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confidence: 99%

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Distribution of gamma-glutamyl transpeptidase and glutaminase isoenzymes in the rabbit single nephron.

1982

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Distribution of gamma-glutamyl transpeptidase and glutaminase isoenzymes in the rabbit single nephron.

1982

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“…Rat kidney contains two distinct glutaminase activities: the mitochondrial phosphate-dependent glutaminase and a phosphate-independent, but maleate-stimulated, glutaminase (Katunuma et al, 1967). The latter reaction is an activity of the brush-border membrane-associated y-glutamyl transpeptidase (Curthoys & Kuhlenschmidt, 1975).…”

Section: Characterization Of Membrane-associated Glutaminasementioning

confidence: 99%

Inhibition by glutamate of phosphate-dependent glutaminase of rat kidney

Shapiro¹,

Morehouse²,

Curthoys³

1982

Biochemical Journal

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A membrane-associated form of phosphate-dependent glutaminase was derived from sonicated mitochondria and purified essentially free of y-glutamyl transpeptidase activity. Increasing concentrations of phosphate cause a sigmoidal activation of the membrane-bound glutaminase. Phosphate also causes a similar effect on the rate of glutaminase inactivation by the two affinity labels, L-2-amino-4-oxo-5-chloropentanoic acid and 6-diazo-5-oxo-L-norleucine, as observed previously for the solubilized and purified enzyme. Therefore the two forms of glutaminase undergo similar phosphateinduced changes in conformation. A sensitive radioactive assay was developed and used to determine the kinetics of glutamate inhibition of the membrane-associated glutaminase. The Km for glutamine decreases from 36 to 4 mM when the phosphate concentration is increased from 5 to 100mM. Glutamate is a competitive inhibitor with respect to glutamine at both high and low concentrations of phosphate. However, the K, for glutamate is increased from 5 to 52 mM with increasing phosphate concentration. Therefore glutamine and glutamate interact with the same site on the glutaminase, but the specificity of the site is determined by the available phosphate concentration.

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“…Malate dehydrogenase, glutamate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase were assayed by measuring the rate of decrease in absorbance of NADH at 37°C [19-211. Arginase from rat liver and glutaminase from rat kidney were prepared and assayed by the method of Schimke [22] and Katunuma et al [23,24], respectively. Xdnthane oxidase was purified from rat liver [25] and assayed by the method of Morel1 [26].…”

Section: Preparations and Assays Of Substrate Enzymesmentioning

confidence: 99%

Studies on New Intracellular Proteases in Various Organs of Rat

Katunuma

Kominami

Kobayashi

et al. 1975

European Journal of Biochemistry

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122

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1. Specific proteases which inactivate the apo-proteins of many pyridoxal enzymes were found in skeletal muscle, liver and small intestine of rats. The protease from these three organs were purified and their properties were compared.2. The purified proteases from liver and skeletal muscle appeared homogeneous on acrylamide gel electrophoresis. Two different proteases were separated from small intestine. A homogeneous, crystalline enzyme was obtained from the muscle layer while enzyme from the mucosa was partially purified.3. They showed substrate specificity for pyridoxal enzymes. Their pH optima were in an alkaline region. They showed activity with the substrate of chymotrypsin, N-acetyl-L-tyrosine ethyl ester, but not with that of trypsin, p-toluenesulfonyl-L-arginine ethyl ester. They were inhibited by pyridoxal phosphate or pyridoxamine phosphate and seryl residues were involved in their active center. 4. 5.The amino acid composition and effect of chemical modifications of the crystalline enzyme from the muscle layer of small intestine were examined to elucidate its active sites and mode of action. Serine and histidine residues were found to be essential for protease activity. A tyrosine residue was also necessary for activity. Modifications of its sulfhydryl group, amino residues and carboxyl group had no effect on its activity.

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Organ specific control of glutamine metabolism

Cited by 79 publications

References 11 publications

Distribution of gamma-glutamyl transpeptidase and glutaminase isoenzymes in the rabbit single nephron.

Distribution of gamma-glutamyl transpeptidase and glutaminase isoenzymes in the rabbit single nephron.

Inhibition by glutamate of phosphate-dependent glutaminase of rat kidney

Studies on New Intracellular Proteases in Various Organs of Rat

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