PMID: 7848284Feb 1, 1995Paper

Activation of hepatic glutaminase by spermine

The Biochemical Journal
Z KovacevicM E Brosnan

Abstract

Glutaminase activity in intact mitochondria from rat liver is activated by spermine, as indicated both by increased glutamate production from glutamine and by increased respiration with glutamine as sole substrate. Glutaminase activity assayed in membranes from frozen-thawed mitochondria, is activated by spermine about 6-fold at physiological concentrations of its other effectors (NH4+ at 0.7 mM, Pi 5 mM) and at pH 7.4. Spermine decreased the apparent Km for glutamine from 38 to 15 mM at 5 mM Pi, and increased the sensitivity of the enzyme for phosphate activation so that the concentration required for 50% stimulation decreased from 15 to 4 mM. Half-maximal spermine effects occurred at 0.15 mM, which is in the physiological range. Spermine was effective in the presence of physiological concentrations of Mg2+. We suggest that spermine may be a physiological activator of hepatic glutaminase.

Citations

Jun 1, 1997·Nitric Oxide : Biology and Chemistry·F BlachierO Soubrane
May 9, 1998·The Journal of Biological Chemistry·J S Rodríguez-Zavala, R Moreno-Sánchez
Nov 20, 2019·International Journal of Biological Macromolecules·Tahany M MaharemYoussef A Said
Feb 2, 2021·Journal of Diabetes and Metabolic Disorders·Lakshmipathi VadlakondaAramati B M Reddy
Nov 20, 1997·Biochimica Et Biophysica Acta·M Madesh, K A Balasubramanian

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