HAIRY (RAMIFIED) REGIONS OF PECTINS .4. OCCURRENCE OF PECTIC HAIRY REGIONS IN VARIOUS PLANT-CELL WALL MATERIALS AND THEIR DEGRADABILITY BY RHAMNOGALACTURONASE
Ha. Schols et Agj. Voragen, HAIRY (RAMIFIED) REGIONS OF PECTINS .4. OCCURRENCE OF PECTIC HAIRY REGIONS IN VARIOUS PLANT-CELL WALL MATERIALS AND THEIR DEGRADABILITY BY RHAMNOGALACTURONASE, Carbohydrate research, 256(1), 1994, pp. 83-95
Pectic polysaccharide fractions of high molecular weight, resistant to
further degradation by pectolytic, hemicellulolytic, and cellulolytic
enzymes, were isolated from potato fibre and from pear, carrot, leek,
and onion tissue by the liquefaction process. The fractions, referred
to as modified hairy regions (MHR), were characterized by the determi
nation of their sugar composition, linkage type composition, degree of
esterification (methyl ester and O-acetyl groups), and molecular weig
ht distribution. Galacturonic acid, galactose, and rhamnose were found
to be the major sugar residues in most of the MHR preparations, while
arabinose was the main sugar in pear MHR. The rhamnose-galacturonic a
cid ratio ranged between 0.44 for pear MHR to 0.63 for MHR from leek.
High degrees of acetylation (da) were calculated assuming that acetyl
groups were only attached to galacturonic acid residues. All MHR fract
ions had a similar molecular weight distribution which was rather hete
rogeneous. It was observed that all MHR preparations were degraded by
RGase in a similar fashion. In all digests, a characteristic populatio
n of reaction products having a molecular weight of ca. 1000-2000, rep
resenting rhamnogalacturonan oligomers, was present. It was concluded
that pectic hairy regions with comparable structural features are comm
on to a variety of fruit and vegetable tissues.