Crystalline structures of poly-d-mannuronic and poly-l-guluronic acids

Abstract

In a recent publication (1) , we show ed that alginic acid preparations enriched in D-mannuronic and L-guIuronic acids gave different x-ray fiber diffraction photographs. We were able to correlate these x-ray fiber diagrams with poly-D -mannuronic acid and poly-L-guluronic acid, resp ectively, and present preliminary details of the two structures. We have now considered the x-ray photographs in greater detall and have supplem ented the x-ray data w ith measurements on oriented films by polarized infrared spectroscopy. We can now present fuller accounts of the crystalline structures of these two substances including the nature of intra- and interchain hydrogen bonding.