Purification and Properties of Uridine Diphosphoglucose 4-epimerase from Escherichia coli*

A method for purification of UDPglucose 4-epimerase from Escherichia coli was described. An overall purification of 80-fold above the crude extract was achieved. With the use of this partially purified enzyme preparation, some of its properties were studied. The Km value is 1.6×10−4M for UDPgalactose and 1.0×10−3M for UDPglucose. The enzyme has a broad pH optimum between 7.5 and 9.0. This enzyme does not require a catalytic amount of NAD for its reaction, and the enzyme activity is not inhibited by p-chloromercuribenzoate.