Biomaterial Database

Uridine-cytidine kinase. III. Competition between uridine and cytidine for a single enzyme. 1977

A S Liacouras, and E P Anderson

The combined phosphorylation of uridine and cytidine by a partially purified preparation of uridine-cytidine kinase has been studied with dual-substrate kinetics. The kinetic patterns obtained are consistent with the theoretical analysis for two competing, alternate substrates interacting with a single enzyme. Thus, despite feedback regulation of the kinase by both UTP and CTP, the results allow a clear conclusion that both nucleosides are phosphorylated by the same enzyme, and probably at a single site, rather than by two closely related isozymes, each specific for one pyrimidine.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
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
D003562	Cytidine	A pyrimidine nucleoside that is composed of the base CYTOSINE linked to the five-carbon sugar D-RIBOSE.	Cytosine Ribonucleoside,Cytosine Riboside,Ribonucleoside, Cytosine,Riboside, Cytosine
D003570	Cytidine Triphosphate	Cytidine 5'-(tetrahydrogen triphosphate). A cytosine nucleotide containing three phosphate groups esterified to the sugar moiety.	CTP,CRPPP,Magnesium CTP,Mg CTP,Triphosphate, Cytidine
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
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D014529	Uridine	A ribonucleoside in which RIBOSE is linked to URACIL.	Allo-Uridine,Allouridine,Allo Uridine
D014541	Uridine Kinase	An enzyme that catalyzes the phosphorylation of uridine and cytidine to uridine 5'-phosphate and cytidine 5'-phosphate, respectively. ATP, dUTP, dGTP, and dATP are effective phosphate donors. EC 2.7.1.48.	Cytidine Kinase,Uridine-Cytidine Kinase,Kinase, Cytidine,Kinase, Uridine,Kinase, Uridine-Cytidine,Uridine Cytidine Kinase
D014544	Uridine Triphosphate	Uridine 5'-(tetrahydrogen triphosphate). A uracil nucleotide containing three phosphate groups esterified to the sugar moiety.	UTP,Magnesium UTP,Magnesium Uridine Triphosphate,Mg-UTP,Mg UTP,Triphosphate, Magnesium Uridine,Triphosphate, Uridine,UTP, Magnesium