THE EFFECT OF ANOMERISM AND HYDRATION ON THE C-O-S VIBRATIONAL FREQUENCY OF D-GALACTOSE-3-SULFATE DETERMINED BY FTIR SPECTROSCOPY

The effect of the anomeric structure of D-galactose-3-sulfate (potassi um salt) on its spectral characteristics was studied by H-1 and C-13 N MR and FTIR spectroscopy under a variety of conditions. The synthetic product in D2O was a mixture of alpha and beta galactopyranose-3-sulfa te. Crystallization from 80% ethanol yielded the alpha anomer in a hig h state of purity. The FTIR spectrum of the C-O-S vibrational bands in the region 900-800 cm(-1) depended on the anomeric structure and on h ydration. In the dry state the alpha anomer had a band at 868 cm(-1) w hile the beta anomer had bands at 882 and 831 cm(-1). In D2O the band at 868 cm(-1) shifted down to 849 cm(-1) for the alpha anomer and that at 831 cm(-1) shifted down to 821 cm(-1) for the alpha anomer. These differences in frequency will be useful as a diagnostic tool in determ ining the configuration at C-1 of galactose-3-sulfate units present in many molecules of biological importance. (C) 1997 Elsevier Science Lt d.