Inactivation of the pyruvate dehydrogenase complex of Escherichia coli by fluoropyruvate
- Univ. of Wisconsin, Madison (USA)
The pyruvate dehydrogenase complex (PDH complex) of Escherichia coli and its pyruvate dehydrogenease component (E{sub 1}) are rapidly inactivated by low concentrations of fluoropyruvate in a thiamin pyrophosphate (TPP) dependent process. The inactivation rates for the PDH complex and for its E{sub 1} component are similar. Pyruvate protects the PDH complex and the E{sub 1} component against inactivation by fluoropyruvate. Dihydrolipoamide protects the E{sub 1} component from inactivation. TPP is not covalently bound to the PDH complex or to the E{sub 1} component by the inactivating reaction. When ({sup 14}C)fluoropyruvate is used to inactivate the PDH complex, {sup 14}C remains bound to the complex after gel filtration. This bound radioactivity is cleaved from the protein by NH{sub 2}OH, {sup {minus}}OH, and NaBH{sub 4} but not by dilute acid. When released by {sup {minus}}OH, greater than 90% of the {sup 14}C cochromatographs with acetate on DEAE-Sephadex. When released by NaBH{sub 4}, and {sup 14}C is recovered as ({sup 14}C)ethanol. Colorimetric analysis for sulfhydryl groups on the native E{sub 1} component and the inactivated E{sub 1} component, using 5,5{prime}-dithiobis(2-nitrobenzoate), reveals that complete inactivation results from covalent modification of 1.37 {plus minus} 0.03 sulfhydryl residues. Fluoropyruvate is known to generate acetyl-TPP at the active of E{sub 1}. The available evidence indicates that acetylation of a sulfhydryl group by acetyl-TPP at the active site of the E{sub 1} component inactivates the enzyme.
- OSTI ID:
- 6855470
- Journal Information:
- Biochemistry; (USA), Vol. 28:25; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON 14 COMPOUNDS
TRACER TECHNIQUES
FLUORINATED ALIPHATIC HYDROCARBONS
BIOLOGICAL EFFECTS
HEMIACETAL DEHYDROGENASES
INACTIVATION
CYSTEINE
ESCHERICHIA COLI
ETHANOL
ION EXCHANGE CHROMATOGRAPHY
UREA
ALCOHOLS
AMIDES
AMINO ACIDS
BACTERIA
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACIDS
CHROMATOGRAPHY
ENZYMES
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDOREDUCTASES
SEPARATION PROCESSES
THIOLS
550201* - Biochemistry- Tracer Techniques