Differential sensitivity of the brain ATP-dependent and GTP-dependent succinyl-CoA synthetase to vanadium ions. Developmental aspects.
We have recently found that both vanadate and vanadyl inhibit ATP-dependent succinyl-CoA synthetase (A-SCS) solubilized from the rat brain mitochondria. Aim of the present study was to estimate a proportion of A-SCS to G-SCS in adult and 5-day-old rat brain and their susceptibility to vanadium ions. The G-SCS to A-SCS ratio of 5-day-old brains was by 196% higher than that in adults. This is in accordance with previous observation that G-SCS is high in tissues metabolizing ketone bodies. Both G-SCS and A-SCS differ in their susceptibility towards vanadium ions. A-SCS of adult brain was more sensitive to vanadate (IC 50 1.6.10(-5) mol.l-1) than was G-SCS (IC 50 6.2.10(-5) mol.l-1). On the contrary G-SCS was more sensitive to vanadyl (IC 50 3.5.10(-4) mol.l-1) than was A-SCS (IC 50 9.0.10(-4) mol.l-1). Also autophosphorylation of G-SCS a-subunit was more resistant to vanadate than A-SCS. In contrast to the adult SCS forms, almost equal susceptibility of A-SCS and G-SCS to vanadyl and vanadate was observed in infant brains. The results suggest some structural (functional) differences between two SCS forms in adults and also between infant and adult G-SCS.
Krivánek
J
J
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Nováková
L
L
D000375:Aging / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D007477:Ions; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013389:Succinate-CoA Ligases / Q000096:biosynthesis*; D014639:Vanadium / Q000494:pharmacology*; D017968:Vanadium Compounds
D007477:Ions; D017968:Vanadium Compounds; D014639:Vanadium; C034028:vanadyl sulfate; D013389:Succinate-CoA Ligases