Myoinosose-2 1-phosphate: an intermediate in the myoinositol 1-phosphate synthase reaction.
Partially purified testicular myoinositol 1-phosphate synthase was incubated with glucose 6-phosphate and NAD+. After 2 min the reaction was stopped by the addition of NaB3H4. Phosphorylated reduced sugars were isolated by ion exchange and dephosphorylated enzymatically. Scylloinositol and myoinositol, added as carriers, were re-isolated and purified to constant specific radioactivity. Since scylloinositol phosphate is uniquely related to myoinosose-2 1-phosphate, the finding of labeled scylloinositol and myoinositol is considered strong evidence for the presence of myoinosose-2 1-phosphate, an intermediate which has been postulated in the synthase-catalyzed isomerization of glucose 6-phosphate to myoinositol 1-phosphate. About one-half the amount of intermediate was demonstrable with boiled synthase, indicating firm binding of myoinosose-2 phosphate to the enzyme.
D000818:Animals; D002238:Carbohydrate Epimerases / Q000378:metabolism*; D002849:Chromatography, Gas; D002854:Chromatography, Paper; D005965:Glucuronates; D007294:Inositol; D007668:Kidney / Q000201:enzymology; D008297:Male; D009943:Organophosphorus Compounds; D010105:Oxygenases; D051381:Rats; D013737:Testis / Q000201:enzymology
D005965:Glucuronates; D009943:Organophosphorus Compounds; D007294:Inositol; D010105:Oxygenases; D002238:Carbohydrate Epimerases