Purification and characterization of selenocysteine beta-lyase from Citrobacter freundii

Journal Article · Thu Aug 01 04:00:00 EDT 1985 · J. Bacteriol.; (United States)

OSTI ID:6085771

Chocat, P; Esaki, N; Tanizawa, K; Nakamura, K; Tanaka, H; Soda, K

The purification and characterization of bacterial selenocysteine beta-lyase, an enzyme which specifically catalyzes the cleavage of L-selenocysteine to L-alanine and Se0, are presented. The enzyme, purified to near homogeneity from Citrobacter freundii, is monomeric with a molecular weight of ca. 64,000 and contains 1 mol of pyridoxal 5'-phosphate as a cofactor per mol of enzyme. L-Selenocysteine is the sole substrate. L-Cysteine is a competitive inhibitor of the enzyme. The enzyme also catalyzes the alpha, beta elimination of beta-chloro-L-alanine to form NH3, pyruvate, and Cl- and is irreversibly inactivated during the reaction. The physicochemical properties, e.g., amino acid composition and subunit structure, of the bacterial enzyme are fairly different from those of the pig liver enzyme. However, the catalytic properties of both enzymes, e.g., substrate specificity and inactivation by the substrate or a mechanism-based inactivator, beta-chloro-L-alanine, are very similar.

• Research Organization: Kyoto Univ., Japan
• OSTI ID: 6085771
• Journal Information: J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 2; ISSN JOBAA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALANINE-ALPHA
ALANINE-L
ALANINES
AMINO ACID SEQUENCE
AMINO ACIDS
BACTERIA
BIOCHEMICAL REACTION KINETICS
CARBON-CARBON LYASES
CARBOXYLIC ACIDS
CHALCOGENIDES
CYSTEINE
DEUTERIUM COMPOUNDS
ENZYMES
HYDROGEN COMPOUNDS
KINETICS
LABELLED COMPOUNDS
LYASES
MICROORGANISMS
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SELENIUM COMPOUNDS
SELENIUM OXIDES
THIOLS
TRITIUM COMPOUNDS