Enzymology of Human Fetal Liver Inositol Synthase

Myo-inositol is an essential molecule which plays a central role in many biochemical processes within the cells including stress response and signal transduction. L-myo-inositol-1-phosphate synthase (MIPS) is the principal enzyme for its biosynthesis. This book, describes the enzymological studies on the isolation and fundamental characterization of the enzyme from human fetal liver which has so far been remained unrepresented. Appreciable L-myo-inositol-1-phosphate synthase activity has been detected in human fetal liver during its intrauterine life. This enzyme preparation from the described source specifically utilized D-glucose-6-phosphate and ¿-NAD+ as its substrate and co-factor respectively. The Km for glucose-6-phospahte and ¿-NAD+ were approximately 1.15 mM, and 0.12 mM while the Vmax values for the same were 280 nM and 252 nM respectively. NH4+ ion had been found as a powerful activator for the enzyme. The apparent molecular weight of the native human fetal liver MIPS was determined to be 170 kDA. The results presented in this book may form a suitable basic study for further research on human cyclitol biochemistry