PARTIAL PURIFICATION AND PROPERTIES OF L-GLUTAMINE: D-FRUCTOSE 6-P AMIDOTRANSFERASE FROM HUMAN PLACENTA

Abstract

The first enzyme of the pathway for uridine diphosphate N-acetyl-D-glucosamine (UDPAG) biosynthesis i.e. L-glutamine: D-fructose 6-P amidotransferase (E.C. 2.6.1.16) was purified 52-fold from human placenta using methanol fractionation and column chromatography on DEAE-Sephadex A-50. The enzyme showed optimal activity in a broad range of pH from 5.8 to 7.8 in both phosphate and cacodylate buffers. Its K m value for D-fructose 6-P was found to be 2.14 mM. The enzyme was inhibited up to 76% in the presence of 0.12mM UDPAG. A K value of 6.6 ?M was obtained for the feedback inhibition of this enzyme by UDPAG