α Ketoglutaric Acid Formation in Human Erythrocytes

Mircevová, L; Biganová, Jana

doi:10.1111/j.1423-0410.1963.tb04154.x

Cited by 5 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the emergence of glutamate cannot be tracked directly, the rate of decrease of added α‐ketoglutarate and alanine seen in the 1 H NMR spectra of haemolysates could only be explained by the formation of glutamate [23]. These studies provided the values of enzyme kinetic parameters for alanine aminotransferase that were similar to previous measurements made using isolated RBC enzymes.…”

Section: Discussionmentioning

confidence: 54%

“…1). The RBC lacks an intact Krebs cycle so α‐ketoglutarate is not used to generate energy as in most cells [23]. The plasma concentration of the substrates, rates of transport across the RBC membrane, and enzymatic conversion to glutamate all determine the contribution of each of these substrates to the provision of glutamate for GSH synthesis.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Glutamine and α‐ketoglutarate as glutamate sources for glutathione synthesis in human erythrocytes

et al. 2011

View full text Add to dashboard Cite

Glutathione (GSH) is an intracellular antioxidant synthesized from glutamate, cysteine and glycine. The human erythrocyte (red blood cell, RBC) requires a continuous supply of glutamate to prevent the limitation of GSH synthesis in the presence of sufficient cysteine, but the RBC membrane is almost impermeable to glutamate. As optimal GSH synthesis is important in diseases associated with oxidative stress, we compared the rate of synthesis using two potential glutamate substrates, a-ketoglutarate and glutamine. Both substrates traverse the RBC membrane rapidly relative to many other metabolites. In whole RBCs partially depleted of intracellular GSH and glutamate, 10 mM extracellular a-ketoglutarate, but not 10 mM glutamine, significantly increased the rate of GSH synthesis (0.85 ± 0.09 and 0.61 ± 0.18 lmolAE(L RBC) , while the initial rate for 0.8 mM a-ketoglutarate was 0.97 lmolAE(L RBC) )1 AEmin )1. However, with normal plasma concentrations, the calculated rate of GSH synthesis was higher with glutamine than with a-ketoglutarate (0.31 and 0.25 lmolAE(L RBC) )1 AEmin)1 , respectively), due to the substantially higher plasma concentration of glutamine. Thus, a potential protocol to maximize the rate of GSH synthesis would be to administer a cysteine precursor plus a source of a-ketoglutarate and ⁄ or glutamine. DatabaseThe mathematical models described here have been submitted to the Online Cellular Systems Modelling Database and can be accessed at http://jjj.biochem.sun.ac.za/database/Whillier/ index.html free of charge.

show abstract

Section: Discussionmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Glutamine and α‐ketoglutarate as glutamate sources for glutathione synthesis in human erythrocytes

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The possible role of blood cells in urea production is discussed.Little is known about the role of blood cells in nitrogen metabolism in animals.Yunis and Arimura [1965] and Rohrs and Archdeacon [1967] investigated the passage of aminoacids through the erythrocyte membrane. Human erythrocytes contain transaminases [Mircevova, Jirgl and Vosykova, 1960] and arginase [Reynolds, Follete and Valentine, 1957]. Soupart [1962] found no arginine in human erythrocytes, or at most a small amount.…”

mentioning

confidence: 99%

Arginine Metabolism in the Blood Cells of Cattle and Goats

Barej¹,

Hill²

1970

Exp Physiol

View full text Add to dashboard Cite

Active arginase was found in the cells of cattle blood, but not in those of goats. Blood cells of cows contained no arginine. When 14C arginine was incubated with the blood of cows, 14C ornithine could be detected in both cells and plasma. More arginine was found in the cells of goat blood than in the plasma. After incubation with 14C arginine, no 14C ornithine was found in goat blood. The possible role of blood cells in urea production is discussed.Little is known about the role of blood cells in nitrogen metabolism in animals.Yunis and Arimura [1965] and Rohrs and Archdeacon [1967] investigated the passage of aminoacids through the erythrocyte membrane. Human erythrocytes contain transaminases [Mircevova, Jirgl and Vosykova, 1960] and arginase [Reynolds, Follete and Valentine, 1957]. Soupart [1962] found no arginine in human erythrocytes, or at most a small amount. Kulasek, Garwacki and Barej [1969] measured free aminoacids in the plasma and blood cells of sheep. They detected no arginine in the cells and attributed this to the presence of arginase there. Barej [unpublished] compared the concentration of free aminoacids in the blood cells of cattle and goats; goat cells contained arginine, but cattle cells did not. This finding prompted the present investigation of arginase activity and arginine metabolism in the blood of cows and goats. METHODSIn vivo. Blood was collected from twenty-five cows in the slaughterhouse. Samples of liver and of rumen mucosa were taken from fifteen cows as soon as possible after slaughter. The animals were of varying age and condition. Blood was collected from twelve goats before and after the morning feed. Liver and rumen mucosa were taken from one goat after slaughter. Arginase activity in plasma, blood cells, liver and rumen mucosa of both cows and goats was determined according to Brown and Cohen [1959].In vitro. Aliquots of 60 ml. of fresh heparinized blood from two cows and two goats were incubated with 0-2 ,uC of 14C arginine, uniformly labelled (The Radiochemical Centre, Amersham). Incubation in a water bath at 38°C lasted 90 or 120 min. The blood was gently shaken during incubation. At 5, 40, 90 and 120 min after the start of incubation samples were taken for measurement of arginase activity and aminoacid concentration. Free aminoacids were estimated in plasma and cells separately, by Moore and Stein's method using the Locarte automatic aminoacid analyser. The blood was centrifuged and kept at 5°C. The cells were washed with saline before haemolysis. The labelled 14C aminoacids in plasma and blood cells were estimated by a Packard Tri-Carb Spectrometer directly connected to the aminoacid analyser.

show abstract

Some current concepts of red cell metabolism

Spear

Sass

1964

Metabolism

View full text Add to dashboard Cite

α Ketoglutaric Acid Formation in Human Erythrocytes

Cited by 5 publications

References 6 publications

Glutamine and α‐ketoglutarate as glutamate sources for glutathione synthesis in human erythrocytes

Glutamine and α‐ketoglutarate as glutamate sources for glutathione synthesis in human erythrocytes

Arginine Metabolism in the Blood Cells of Cattle and Goats

Some current concepts of red cell metabolism

Contact Info

Product

Resources

About