Studies on the chemical mechanism of E. coli pyruvate-formate lyase

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6373342

Brush, E J; Lipsett, K A; Kozarich, J W

Pyruvate-formate lyase (PFL) catalyzes the CoA dependent dismutation of pyruvate into acetyl-CoA and formate. The activated enzyme contains a radical moiety essential for this reaction. They have initiated studies to elucidate the mechanism by which this enzymic process occurs. Their studies have centered on the inactivation of PFL by a variety of pyruvate and formate analogs, including the known inhibitors O/sub 2/, hypophosphite, and 3-fluoropyruvate, and by some newly discovered compounds, propargylic and acrylic acids. Inactivation is first order, and readily observable at inhibitor concentrations of 5 mM or less. Propargylic acid is especially reactive; at 1 mM the enzyme half-life is 2 minutes. Furthermore, a variety of other acetylenic analogs such as acetylene dicarboxylate, 2-butynoate, and propargyl alcohol do not inhibit PFL, suggesting some specificity for propargylic acid. Of particular significance is their finding of isotope effects on the rate of inactivation by /sup 2/H/sub 2/-hypophosphite and 3-/sup 2/H-propargylic acid (3.2 at 1 mM). Such data suggest to us that inactivation may involve rate-determining hydrogen abstraction or hydrogen shift from the inhibitor molecule. Anaerobic gel filtration of chemically inactivated enzyme does not lead to recovery of activity, although subsequent treatment with a PFL activating system does lead to partial activity restoration.

• Research Organization: Univ. of Maryland, College Park
• OSTI ID: 6373342
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL PATHWAYS
CARBOXYLIC ACIDS
DEUTERIUM
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ESCHERICHIA COLI
FORMIC ACID
HYDROGEN ISOTOPES
INHIBITION
ISOTOPE APPLICATIONS
ISOTOPE EFFECTS
ISOTOPES
KETO ACIDS
KINETICS
LIGHT NUCLEI
LYASES
METABOLISM
MICROORGANISMS
MONOCARBOXYLIC ACIDS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PYRUVIC ACID
REACTION KINETICS
STABLE ISOTOPES
TRACER TECHNIQUES