FINE CHEMICAL STRUCTURE ANALYSIS OF OLIGOSACCHARIDES PRODUCED BY AN ULVAN-LYASE DEGRADATION OF THE WATER-SOLUBLE CELL-WALL POLYSACCHARIDES FROM ULVA SP. (ULVALES, CHLOROPHYTA)

摘要

A marine bacterium degrading the water-soluble cell wall polysaccharides from Ulva sp. (ulvan) has been isolated. The good correlation between ulvan degradation monitored by reducing-power, UV absorbance and viscosimetry, indicated that the crude enzymatic extract contains essentially an endo-ulvan lyase activity. This activity was rapidly inhibited by the reaction products which consisted of a series of ulvanobiouronic acid A 3-sulfate [--> 4)-beta-D-GlcpA-(1 --> 4)-alpha-L-Rhap 3-sulfate-(1 -->]n with 4-deoxy-L-threo-hex-4-enopyranosiduronic acid at the non-reducing end. Other deviant repeating structures with beta-D-Xylp or alpha-L-IdopA replacing beta-D-GlcpA in the repeating ulvanobiouronic acid disaccharide and the presence of two consecutive (I --> 4) linked beta-D-GlcpA demonstrated the great variability and complexity of ulvan chemical structure. (C) 1997 Elsevier Science Ltd. All rights reserved. [References: 22]