Biomaterial Database

Studies on the allosteric nature of acetate kinase from Bacillus stearothermophilus. 1979

H Nakajima, and K Suzuki, and K Imahori

Fructose 1,6-bisphosphate (FBP) stimulates the reaction of Bacillus stearothermophilus acetate kinase (AK). FBP changes the reaction curve for ATP from a sigmoidal type to a Michaelis-Menten one. The binding of FBP to AK was studied by an equilibrium dialysis method and by measuring changes in fluorescence. The extent of binding of FBP to the enzyme paralleled its activation. In addition, the binding constant for FBP increased in the presence of substrate, ATP. These results suggest that FBP is an allosteric activator of B. stearothermophilus AK. Only two moles of FBP bound to this tetrameric enzyme. No cooperativity was found for the binding of FBP. These observations support the previous conclusion, that a set of two subunits in the tetramer is a unit of the enzymatic function. A model is presented to interpret the sigmoidal kinetics for ATP, the absence of cooperativity for FBP binding, and the allosteric activation by FBP of this enzyme. The kinetic properties of the enzyme can be explained quantitatively by this model.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D010770	Phosphotransferases	A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.	Kinases,Phosphotransferase,Phosphotransferases, ATP,Transphosphorylase,Transphosphorylases,Kinase,ATP Phosphotransferases
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005635	Fructosediphosphates	Diphosphoric acid esters of fructose. The fructose-1,6- diphosphate isomer is most prevalent. It is an important intermediate in the glycolysis process.
D000084	Acetate Kinase	An enzyme that catalyzes reversibly the phosphorylation of acetate in the presence of a divalent cation and ATP with the formation of acetylphosphate and ADP. It is important in the glycolysis process. EC 2.7.2.1.	Acetokinase,Kinase, Acetate
D000494	Allosteric Regulation	The modification of the reactivity of ENZYMES by the binding of effectors to sites (ALLOSTERIC SITES) on the enzymes other than the substrate BINDING SITES.	Regulation, Allosteric,Allosteric Regulations,Regulations, Allosteric
D000495	Allosteric Site	A site on an enzyme which upon binding of a modulator, causes the enzyme to undergo a conformational change that may alter its catalytic or binding properties.	Allosteric Sites,Site, Allosteric,Sites, Allosteric
D001411	Geobacillus stearothermophilus	A species of GRAM-POSITIVE ENDOSPORE-FORMING BACTERIA in the family BACILLACEAE, found in soil, hot springs, Arctic waters, ocean sediments, and spoiled food products.	Bacillus stearothermophilus,Bacillus thermoliquefaciens
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence