Structural and regulatory properties of pyruvate kinase from Pseudomonas citronellolis

Journal Article · Mon Sep 10 04:00:00 EDT 1979 · J. Biol. Chem.; (United States)

OSTI ID:5373814

Chuang, D T; Utter, M F

Pseudomonas citronellolis contains a single variety of pyruvate kinase regardless of the substrate on which the organism is grown. The enzyme has been purified to homogeneity and shown by cross-linking and gel electrophoretic studies to be a tetramer of M/sub r/ = 225,000 to 240,000. Unlike pyruvate kinases from yeast, liver, kidney, and red cells, the Pseudomonas enzyme is not affected by fructose 1,6-bisphosphate. However, it is activated by 2-keto-3-deoxy-6-phosphogluconate (KDPG), an intermediate of the Entner-Doudoroff pathway which is utilized for glucose catabolism by this organism. The Pseudomonas enzyme is also activated by ribose-5-P,5'-AMP, and fructose-6-P. Kinetic studies suggest that this group of metabolites may act at a single site with KDPG activation occurring at a separate site. All of the activators function by increasing the affinity of the enzyme for P-enolpyruvate. The latter substrate shows a strong positive cooperativity with the enzyme which is lowered or abolished by the presence of the activators. A strong synergistic effect exists between KDPG and ribose-5-P as exhibited by a mutual lowering of the concentrations required for activation as well as by a more than additive effect on the enzyme's affinity for P-enolpyruvate. Pyruvate kinase from P. citronellolis also differs from most varieties of the enzyme in that it is not activated by K/sup +/ orNH/sub 4//sup +/, requires high concentrations of Mg/sup 2 +/ and is relatively nonspecific with respect to its nucleoside diphosphate substrate.

• Research Organization: Case Western Reserve Univ., Cleveland, OH
• OSTI ID: 5373814
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 254:17; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
AMP
BACTERIA
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACIDS
ELECTROPHORESIS
ENZYMES
KETO ACIDS
KINETICS
METABOLISM
MICROORGANISMS
MOLECULAR STRUCTURE
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHOTRANSFERASES
PSEUDOMONAS
PYRUVIC ACID
REACTION KINETICS
SUBSTRATES
TRANSFERASES