Large-scale preparation of the oligosaccharide phosphate fraction of Pichia holstii NRRL Y-2448 phosphomannan for use in the manufacture of PI-88

Abstract

Mild acid-catalysed hydrolysis of the extracellular phosphomannan of the yeast Pichia holstii NRRL Y-2448 produces a high-molecular-weight phosphomannan core, a low-molecular-weight oligosaccharide phosphate fraction, and a neutral oligosaccharide fraction. A method was developed for the large-scale preparation of the oligosaccharide phosphate fraction, consisting predominantly of the pentasaccharide phosphate, 6- O-PO 3H 2-α- d-Man-(1→3)-α- d-Man-(1→3)-α- d-Man-(1→3)-α- d-Man-(1→2)- d-Man, for use in the manufacture of the promising new anti-cancer agent, PI-88. Further insights were also gained into the structure of the phosphomannan by HPLC analysis of the time course of the hydrolysis reaction.