Kinetic properties of hexose-monophosphate dehydrogenases. I. Isolation and partial purification of glucose-6-phosphate dehydrogenase from rat liver and kidney cortex

1. 3-Hydroxybutyrate dehydrogenase (EC 1.1.1.30) activities in sheep kidney cortex, rumen epithelium, skeletal muscle, brain, heart and liver were 177, 41, 38, 33, 27 and 17μmol/h per g of tissue respectively, and in rat liver and kidney cortex the values were 1150 and 170 respectively. 2. In sheep liver and kidney cortex the 3-hydroxybutyrate dehydrogenase was located predominantly in the cytosol fractions. In contrast, the enzyme was found in the mitochondria in rat liver and kidney cortex. 3. Laurate, myristate, palmitate and stearate were not oxidized by sheep liver mitochondria, whereas the l-carnitine esters were oxidized at appreciable rates. The free acids were readily oxidized by rat liver mitochondria. 4. During oxidation of palmitoyl-l-carnitine by sheep liver mitochondria, acetoacetate production accounted for 63% of the oxygen uptake. No 3-hydroxybutyrate was formed, even after 10min anaerobic incubation, except when sheep liver cytosol was added. With rat liver mitochondria, half of the preformed acetoacetate was converted into 3-hydroxybutyrate after anaerobic incubation. 5. Measurement of ketone bodies by using specific enzymic methods (Williamson, Mellanby & Krebs, 1962) showed that blood of normal sheep and cattle has a high [3-hydroxybutyrate]/[acetoacetate] ratio, in contrast with that of non-ruminants (rats and pigeons). This ratio in the blood of lambs was similar to that of non-ruminants. The ratio in sheep blood decreased on starvation and rose again on re-feeding. 6. The physiological implications of the low activity of 3-hydroxybutyrate dehydrogenase in sheep liver and the fact that it is found in the cytoplasm in sheep liver and kidney cortex are discussed.

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The Effect of Temperature on the Uptake of Radiosulfate by Rat Renal Tissue from Radiosulfate-Containing Solutions in Vitro

The Journal of General Physiology ◽

10.1085/jgp.44.3.555 ◽

1961 ◽

Vol 44 (3) ◽

pp. 555-569 ◽

Cited By ~ 5

Author(s):

Ingrith J. Deyrup ◽

R. E. Davies

Keyword(s):

Rat Liver ◽

Incubation Medium ◽

Renal Tissue ◽

Effect Of Temperature ◽

Kidney Cortex ◽

Liver And Kidney ◽

Cortex Slices ◽

Kidney Cortex Slices

Kidney cortex slices incubated in vitro at 0°C. accumulate radiosulfate from the incubation medium. This process differs from the previously described uptake of radiosulfate by renal tissue incubated at 38°C., for instance, in the lesser sensitivity of the uptake at 0°C. to differential effects of Na+ as compared with K+ ions, and of sucrose as compared with glucose. Phlorizin inhibits radiosulfate accumulation at 0°C., whereas it enhances the uptake at 38°C. Effects of the cations K+ and Na+ and of phlorizin at temperatures intermediate between 0° and 38°C. have been studied. Parallels have been noted between the accumulative processes for radiosulfate of kidney slices maintained at 0°C. and of mitochondria isolated from rat liver and kidney cortex. These similarities may be attributed to an important role of radiosulfate uptake by mitochondria in slice accumulation of radiosulfate in the cold.

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Effects of ischaemia on content of metabolites in rat liver and kidney in vivo

Biochemical Journal ◽

10.1042/bj1200105 ◽

1970 ◽

Vol 120 (1) ◽

pp. 105-111 ◽

Cited By ~ 162

Author(s):

D. A. Hems ◽

J. T. Brosnan

Keyword(s):

Rat Liver ◽

Glycogen Phosphorylase ◽

Time Course ◽

Kidney Cortex ◽

Redox States ◽

Renal Ischaemia ◽

Glycolytic Intermediates ◽

Liver And Kidney

1. The time-course of changes in content of intermediates of glycolysis in rat liver and kidney cortex after severance of blood supply was investigated. 2. The decline in content of ATP was more rapid in kidney (1.7–0.5μmol/g in 30s) than in liver (2.7–1.6μmol/g in 60s). In both tissues AMP and Pi accumulated. 3. Net formation of lactate was 1.7μmol/g during the second minute of ischaemia in liver from well-fed rats, 1.1μmol/g in liver from 48h-starved rats, and about 1.0μmol/g during the first 30s of ischaemia in kidney. Net formation of α-glycerophosphate was rapid, especially in liver. 4. In kidney the concentration of β-hydroxybutyrate rose, but that of α-oxoglutarate and acetoacetate decreased. 5. In both organs the concentrations of fructose diphosphate and triose phosphates increased during ischaemia and those of other phosphorylated C3 intermediates decreased. 6. The concentration of the hexose 6-phosphates rose rapidly during the first minute of ischaemia in liver, but decreased during renal ischaemia. 7. In kidney the content of glutamine fell after 2min of ischaemia, and that of ammonia and glutamate rose. 8. The redox states of the cytoplasmic and mitochondrial NAD couple in kidney cortex were similar to those in liver. 9. The regulatory role of glycogen phosphorylase, pyruvate kinase and phosphofructokinase is discussed in relation to the observed changes in the concentrations of the glycolytic intermediates.

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Partial purification and some kinetic properties of glucose-6-phosphate dehydrogenase from Phycomyces blakesleeanus

Biochimie ◽

10.1016/s0300-9084(86)80026-8 ◽

1986 ◽

Vol 68 (2) ◽

pp. 293-302 ◽

Cited By ~ 7

Author(s):

Dolores De Arriaga ◽

Sol Montero ◽

Félix Busto ◽

Joaquín Soler

Keyword(s):

Partial Purification ◽

Kinetic Properties ◽

Phycomyces Blakesleeanus ◽

Glucose 6 Phosphate Dehydrogenase

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O n the Mechanism of Inactivation and ATP-Dependent Reactivation of Rat Liver Tyrosine Aminotransferase

Zeitschrift für Naturforschung C ◽

10.1515/znc-1977-9-1019 ◽

1977 ◽

Vol 32 (9-10) ◽

pp. 777-780 ◽

Cited By ~ 2

Author(s):

Hans-Heinrich Hamm ◽

Werner Seubert

Keyword(s):

Rat Liver ◽

Tyrosine Aminotransferase ◽

Particulate Fraction ◽

Kidney Cortex ◽

Aminotransferase Activity ◽

Liver And Kidney ◽

Membrane Bound ◽

Nucleotide Specificity

Abstract The mechanism of in vitro inactivation and ATP-dependent rapid reactivation of rat liver tyrosine aminotransferase by a membrane-bound system from rat liver and kidney cortex and the nucleotide specificity of this process was investigated using partially purified tyrosine amino transferase as a substrate. Adenosine 5′-triphosphate (ATP) could be replaced by guanosine 5′-tri-phosphate (GTP), whereas inosine 5′-triphosphate (ITP) was less effective. During reactivation [γ-32P]A T P was incorporated into the enzyme and not excorporated by incubation of the labeled enzyme with excess non-radioative ATP. Inactivation of labeled tyrosine aminotransferase by a particulate fraction led to a decrease protein-bound radioactivity concomitant with an increase of [32P] orthophosphate. This points to a phosphorylation and dephosphorylation mechanism in the regulation of tyrosine aminotransferase activity.

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