Some Enzymic Properties of Mitochondrial Propionyl Carboxylase

Halenz, Donald R.; Feng, Jan-Yung; Hegre, C. S.; Lane, M. Daniel

doi:10.1016/s0021-9258(19)63410-1

Cited by 50 publications

(3 citation statements)

References 17 publications

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“…The apparent Km values for acetyl-, propionyl-, and butyryl-CoA ranged between 0.2 and 0.4 mM. These Km values compare well with those reported on mammalian propionyl-CoA carboxylases (Halenz et al, 1962) but are ten times higher than the values reported 0 Apparent Km and Fmax values were determined from Lineweaver-Burk plots with all reactants at saturating levels except for the reactant being analyzed. The standard reaction mixture consisted of 80 mM Tris-HCl, pH 8.0, 40 mM KC1, 20 mM NaH14C03,1 mM ATP, 10 mM MgCl2, 1.5 mM acyl-CoA, and enzyme.…”

Section: Resultssupporting

confidence: 79%

“…In accordance with their physiological functions, mammalian acyl-CoA carboxylases are associated with specific subcellular fractions. Acetyl-CoA carboxylase, for example, is located in the cytosol, whereas propionyl-CoA carboxylase is located in the mitochondria (Halenz et al, 1962;Kaziro & Ochoa, 1964). In view of this and the relatively broad substrate specificity of the nematode carboxylase, it seemed desirable to investigate the intracellular location of the enzyme in T. aceti.…”

Section: Resultsmentioning

confidence: 99%

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Acyl-coenzyme A carboxylase of the free-living nematode Turbatrix aceti. 2. Its catalytic properties and activation by monovalent cations

Meyer¹,

Meyer²

1978

Biochemistry

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A highly purified acyl-CoA carboxylase from the nametode Turbatrix aceti catalyzes the ATP, Mg2+, and HCO3- dependent alpha-carboxylation of acetyl-CoA, propionyl-CoA, and butyryl-CoA at the respective rates of 6.8, 39.7, and 9.1 mumol per min per mg. The enzyme is inhibited by avidin and sulfhydryl reagents. It is activated up to 30-fold by the monovalent cations K+, Rb+, Cs+, or NH4+, with the apparent activation constants of 11.0, 4.1, 10.0, and 6.7 mM, respectively. In the presence of K+, the apparent Km for ATP increases 5-fold, and the Km for HCO3- decreases 4-fold, whereas the Km for propionyl-CoA remains constant. Of the partial reactions, the ATP-32P exchange reaction and the carboxylation of free biotin have a nearly absolute requirement for K+. By contrast, the [14C]acetyl-CoA-malonyl-CoA exchange reaction proceeds without K+ at 80% of its maximum rate. The data indicate that K+ primarily stimulates the first half of the carboxylation reaction, i.e., the ATP-dependent carboxylation of the biotinyl residue.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Acyl-coenzyme A carboxylase of the free-living nematode Turbatrix aceti. 2. Its catalytic properties and activation by monovalent cations

Meyer¹,

Meyer²

1978

Biochemistry

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show abstract

“…Table I). However, several workers (Friedman and Stern, 1961;Halenz et al, 1962) have reported that inactivation by avidin can be partially or completely reversed if the biotin carboxylase-avidin complex is subsequently incubated with excess biotin. This problem has been reexamined with pyruvate carboxylase as a possible further approach to elucidation of the structure of the pyruvate carboxylase-avidin complexes.…”

Section: Resultsmentioning

confidence: 99%