The effects of phospholipids on the activation of glutamate dehydrogenase by L-leucine.
Glutamate dehydrogenase in disrupted mitochondrial preparations is activated by L-leucine to a much greater extent than is the purified enzyme. A factor, or factors, responsible for modulating the sensitivity of L-leucine is lost during the purification of the enzyme. Although both cardiolipin and phosphatidylserine are inhibitors of the enzyme, only the inhibition by the former phospholipid is reversed by L-leucine. The inhibition of glutamate dehydrogenase by its binding to cardiolipin in the disrupted mitochondrial preparations and its relief by L-leucine could account for the greater sensitivity of such preparations to activation by that amino acid.
Couée
I
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Department of Biochemistry, Trinity College, Dublin, Ireland.
Tipton
K F
KF
D000818:Animals; D002308:Cardiolipins / Q000494:pharmacology; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D005969:Glutamate Dehydrogenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D007930:Leucine; D008928:Mitochondria / Q000201:enzymology; D010713:Phosphatidylcholines / Q000494:pharmacology; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology*
D002308:Cardiolipins; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; D010743:Phospholipids; D005969:Glutamate Dehydrogenase; D007930:Leucine