Effect of heparin and dextran sulfate on the activity of glutathione reductase from yeast.
Glutathione reductase (EC 1.6.4.2) is a pivotal enzyme of the glutathione antioxidant system in a cell. The kinetic studies of the interaction of glutathione reductase with unfractionated and low molecular weight heparin and dextran sulfate can contribute to explanation of polyanions effect on the conformation changes of glutathione reductase. The tested polyanions inhibit this enzyme and the inhibition effect depends on the ionic strengths and pH value. The most potent inhibitor is dextran sulfate (ID50 is 4.1 micrograms/ml, pH = 6.8, without NaCl). The ionic strength (> 100 mM) allows the reactivating of GR if the concentration of DS is not higher than 80 micrograms/ml. The inhibition effect of tested polyanions is caused by electrostatic interactions with enzyme; the kinetic analyses indicate that it is a mixed inhibition with respect to oxidized glutathione or NADPH.
Paulíková
H
H
Department of Biochemistry, University of P.J. Safárik, Faculty of Sciences, Kosice, Slovakia.
Petricková
I
I
Antalík
M
M
Podhradský
D
D
D000838:Anions; D002384:Catalysis; D016264:Dextran Sulfate / Q000494:pharmacology*; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology*; D006495:Heparin, Low-Molecular-Weight / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D000838:Anions; D006495:Heparin, Low-Molecular-Weight; D006493:Heparin; D016264:Dextran Sulfate; D005980:Glutathione Reductase