Premium
THE INHIBITION OF RAT BRAIN ATP: CITRATE OXALOACETATE‐LYASE BY L‐GLUTAMATE 1
Author(s) -
Szutowicz A.,
Stepie M.,
Angielski S.
Publication year - 1974
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1974.tb12182.x
Subject(s) - glutamate receptor , atp citrate lyase , citrate synthase , lyase , biochemistry , enzyme , amino acid , biology , chemistry , receptor
—1 Among 16 amino acids tested only D‐ and L‐glutamate were found to be specific inhibitors of citrate lyase from adult rat brain. Glutamate also inhibited citrate lyase from the liver of starved animals while it was without effect on lyase from those refed with carbohydrate. L‐Glutamate did not inhibit the citrate lyase from brains of newborn rats. 2 The inhibitory effect of L‐glutamate was increased when the time of preincubation was prolonged, but only in the presence of both ATP and MgCl 2 . This time‐dependent inhibition could be reversed by addition of high concentrations of ATP. 3 L‐Glutamate was without effect on K m and V max values for MgCl 2 . Excess of Mg 2+ ions was indispensable for glutamate inhibition. 4 L‐Glutamate was shown to be competitive with respect to the ATP inhibitor of the lyase, with a K i of 0.3mM. 5 The mechanism of L‐glutamate inhibition may be due to the reaction of a glutamate‐Mg complex with the phosphorylated intermediary form of the lyase, resulting in the formation of a lyase‐glutamate complex. 6 The physiological significance of the inhibitory action of glutamate is discussed.