Ma. Coimbra et al., INVESTIGATION OF THE OCCURRENCE OF XYLAN-XYLOGLUCAN COMPLEXES IN THE CELL-WALLS OF OLIVE PULP (OLEA-EUROPAEA), Carbohydrate polymers, 27(4), 1995, pp. 277-284
Previously we reported the possible occurrence of a complex containing
glucuronoxylan and xyloglucan in the cell walls of olive pulp. In ord
er to investigate the nature of this complex, the 1 M KOH (1 degrees C
)-soluble polysaccharides in which it was prevalent, were separated by
graded ethanol precipitation followed by anion-exchange chromatograph
y. A slightly acidic fraction was obtained and, by methylation analysi
s, glycosidic linkages typical of both xylan and xyloglucan were detec
ted. Two distinct populations of the xylan-xyloglucan complexes were r
esolved by gel-filtration chromatography (2000 and 100 kDa) and the st
ructural features were determined by methylation analysis. Cross-linki
ng of the xylan-xyloglucan moieties was investigated by digestion of t
he xylan component with a purified, specific, endoxylanase. Although o
nly the xylan element was digested, as verified by methylation analysi
s, the molecular weight of the xyloglucan moiety was also reduced. Thi
s confirmed that the xylan and xyloglucan moieties were strongly attac
hed. The occurrence and structure of the xylan-xyloglucan complexes in
the olive pulp cell walls is discussed.