Characterization of four lactose monophosphates by application of 31P-, 13C-, and 1H-N.M.R. spectroscopy

Abstract

By a combination of ion-exchange chromatography and h.p.l.c., two fractions (A and B) have been obtained from pharmaceutical-grade lactose, each containing a mixture of lactose monophosphates. 31P-N.m.r. and 13C-n.m.r. spectroscopic analysis indicated A to contain the 6- and 6Œ-phosphates and B to contain the 3Œ- and 4Œ-phosphates. Application of 2D-13C-1H COSY and 2D-1H-1H COSY afforded 1H-n.m.r. assignments for all protons in all four compounds. The observed 31P-1H and 31C-1H couplings are interpreted in terms of preferred orientations of the phosphate group in each compound.