Reaction of phosphoenolpyruvate carboxylase with (Z)-3-bromophosphoenolpyruvate and (Z)-3-fluorophosphoenolpyruvate
(Z)-3-Bromophosphoenolpyruvate inactivates phosphoenolpyruvate carboxylase from maize in the presence of HCO/sub 3//sup -/ and either Mg/sup 2 +/ or Mn/sup 2 +/. The inactivation rate follows saturation kinetics. Inactivation is slower in the presence of phospholactate or epoxymaleate, both of which are inhibitors of the enzyme, or dithiothreitol. Inactivation is completely prevented by the presence of lactate dehydrogenase and NADH, and 3-bromolactate is formed during this treatment. If the reaction is conducted by using HC/sup 18/O/sub 3//sup -/, the inorganic phosphate produced contains /sup 18/O. This and other evidence indicate that phosphoenolpyruvate carboxylase catalyzes conversion of bromophosphoenolpyruvate into bromopyruvate by way of the usual carboxyphosphate-enolate intermediate, and bromopyruvate is the species responsible for enzyme inactivation. (Z)-3-fluorophosphoenolpyruvate is transformed by the enzyme into a 6:1 mixture of 3-fluoropyruvate and 3-fluorooxalacetate, presumably by the same mechanism. The enzyme is not inactivated during this treatment.
- Research Organization:
- Univ. of Wisconsin, Madison (USA)
- OSTI ID:
- 5272344
- Journal Information:
- Biochemistry; (United States), Vol. 27:4
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
CARBOXY-LYASES
BIOCHEMICAL REACTION KINETICS
MASS SPECTROSCOPY
NUCLEAR MAGNETIC RESONANCE
LABELLED COMPOUNDS
PYRUVIC ACID
BIOCHEMISTRY
BROMINE 79
BROMINE 81
INACTIVATION
MAIZE
MASS SPECTROMETERS
ORGANIC BROMINE COMPOUNDS
OXYGEN 18
PHOSPHORUS 31
BROMINE ISOTOPES
CARBON-CARBON LYASES
CARBOXYLIC ACIDS
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EVEN-EVEN NUCLEI
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INTERMEDIATE MASS NUCLEI
ISOTOPES
KETO ACIDS
KINETICS
LIGHT NUCLEI
LYASES
MAGNETIC RESONANCE
MEASURING INSTRUMENTS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN ISOTOPES
PHOSPHORUS ISOTOPES
PLANTS
RADIOISOTOPES
REACTION KINETICS
RESONANCE
SECONDS LIVING RADIOISOTOPES
SPECTROMETERS
SPECTROSCOPY
STABLE ISOTOPES
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