Rat liver gamma-butyrobetaine hydroxylase catalyzed reaction: influence of potassium, substrates, and substrate analogues on hydroxylation and decarboxylation.

  title={Rat liver gamma-butyrobetaine hydroxylase catalyzed reaction: influence of potassium, substrates, and substrate analogues on hydroxylation and decarboxylation.},
  author={Robert S. Wehbie and N. S. Punekar and Henry A. Lardy},
  volume={27 6},
Interaction of rat liver gamma-butyrobetaine hydroxylase (EC with various ligands was studied by following the decarboxylation of alpha-ketoglutarate, formation of L-carnitine, or both. Potassium ion stimulates rat liver gamma-butyrobetaine hydroxylase catalyzed L-carnitine synthesis and alpha-ketoglutarate decarboxylation by 630% and 240%, respectively, and optimizes the coupling efficiency of these two activities. Affinities for alpha-ketoglutarate and gamma-butyrobetaine are… 
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Cofactor requirements of gamma-butyrobetaine hydroxylase from rat liver.
It is suggested that γ-butyrobetaine is hydroxylated to carnitine simultaneously with the oxidative decarboxylation of 2-ketoglutarate in a reaction sequence which involves the intermediate formation of a peroxide of the two substrates.
Prolyl hydroxylase half reaction: peptidyl prolyl-independent decarboxylation of alpha-ketoglutarate.
It has been found that highly purified preparations of the enzyme can decarboxylate alpha-ketoglutarate in the absence of a peptidyl proline substrate, and Poly(L-proline), a specific inhibitor of prolyl hydroxylation, enhances the uncoupled decar boxylation ofalpha-ketglutarate without itself being hydroxymated.
gamma-butyrobetaine in tissues and serum of fed and starved rats determined by an enzymic radioisotopic procedure.
Starvation for 48 h did not affect the gamma-butyrobetaine concentration in serum, liver and brain, but that in skeletal muscles, kidney and heart was increased, and show that starvation enhances the synthesis and/or the retention of this compound in many tissues.
Interaction of isocitrate dehydrogenase with (RS)-3-bromo-2-ketoglutarate. A potential affinity label for alpha-ketoglutarate binding sites.
Although bromoketoglutarate, as a substrate for isocitrate dehydrogenase, clearly has affinity for the active site, the irreversible inactivation of the enzyme by the reagent may result from modification outside the active-site region, since inactivation during catalytic turnover of bromo-2-ketoglutamate is not observed.
Decarboxylation of alpha-ketoglutarate coupled to collagen proline hydroxylase.
  • R. RhoadsS. Udenfriend
  • Biology, Chemistry
    Proceedings of the National Academy of Sciences of the United States of America
  • 1968
With these preparations, it has now been possible to show a substrate-dependent and stoichiometric decarboxylation of a--ketoglutarate coupled to the hydroxylations of peptidyl proline residues.
The 2-oxoglutarate binding site of prolyl 4-hydroxylase. Identification of distinct subsites and evidence for 2-oxoglutarate decarboxylation in a ligand reaction at the enzyme-bound ferrous ion.
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Use of chromium-adenosine triphosphate and lyxose to elucidate the kinetic mechanism and coordination state of the nucleotide substrate for yeast hexokinase.
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