Enzymatically derived aldouronic acids from Cryptomeria japonica arabinoglucuronoxylan

► Distribution pattern of 4-O-MeGlcA units in arabinoglucuronoxylan. ► Presence of regions of eight contiguous unsubstituted Xyl units. ► Isolation of aldouronic acids containing two MeGlcA units. ► MeGlcA units on two adjacent Xyl units are between single MeGlcA side chains.