Biomaterial Database

UDPGlucose 4-epimerase from Saccharomyces fragilis. Allosteric kinetics with UDP-glucose as substrate. 1975

M Hay, and A Bhaduri

UDPglucose 4-epimerase from Saccharomyces fragilis catalyzes a freely reversible reaction between UDP-galactose and UDP-glucose. With UDP-galactose as the substrate the enzyme shows a classical hyperbolic kinetics but when UDP-glucose is used as the substrate a distinct allostericity is observed. As a consequence, at low concentrations of UDP-glucose, the enzyme fails to establish the equilibrium at a significant rate. Glucose 6-phosphate acts as a strong activator for the enzyme with low concentrations of UDP-glucose as the substrate. In view of these rather unusual kinetic data for an enzyme catalyzing a freely reversible reaction, UDPglucose 4-epimerase may play a regulatory role in controlling the flux of galactose metabolism.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D002238	Carbohydrate Epimerases	Enzymes that catalyze the epimerization of chiral centers within carbohydrates or their derivatives. EC 5.1.3.	Carbohydrate Isomerases,Epimerases, Carbohydrate,Isomerases, Carbohydrate
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
D012440	Saccharomyces	A genus of ascomycetous fungi of the family Saccharomycetaceae, order SACCHAROMYCETALES.	Saccharomyce
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014531	Uridine Diphosphate Galactose	A nucleoside diphosphate sugar which can be epimerized into UDPglucose for entry into the mainstream of carbohydrate metabolism. Serves as a source of galactose in the synthesis of lipopolysaccharides, cerebrosides, and lactose.	UDP Galactose,UDPGal,Uridine Diphosphogalactose,Uridine Pyrophosphogalactose,Diphosphate Galactose, Uridine,Diphosphogalactose, Uridine,Galactose, UDP,Galactose, Uridine Diphosphate,Pyrophosphogalactose, Uridine
D014532	Uridine Diphosphate Glucose	A key intermediate in carbohydrate metabolism. Serves as a precursor of glycogen, can be metabolized into UDPgalactose and UDPglucuronic acid which can then be incorporated into polysaccharides as galactose and glucuronic acid. Also serves as a precursor of sucrose lipopolysaccharides, and glycosphingolipids.	UDP Glucose,UDPG,Uridine Diphosphoglucose,Diphosphate Glucose, Uridine,Diphosphoglucose, Uridine,Glucose, UDP,Glucose, Uridine Diphosphate
D014534	UDPglucose 4-Epimerase	A necessary enzyme in the metabolism of galactose. It reversibly catalyzes the conversion of UDPglucose to UDPgalactose. NAD+ is an essential component for enzymatic activity. EC 5.1.3.2.	UDP Galactose Epimerase,UDP Glucose Epimerase,UDPgalactose 4-Epimerase,Uridine Diphosphate Glucose Epimerase,UDP-Galactose 4-Epimerase,UDP-Glucose 4-Epimerase,4-Epimerase, UDP-Galactose,4-Epimerase, UDP-Glucose,4-Epimerase, UDPgalactose,4-Epimerase, UDPglucose,Epimerase, UDP Galactose,Epimerase, UDP Glucose,Galactose Epimerase, UDP,Glucose Epimerase, UDP,UDP Galactose 4 Epimerase,UDP Glucose 4 Epimerase,UDPgalactose 4 Epimerase,UDPglucose 4 Epimerase