Sugar-beet pulp was de-esterified and submitted to 72 h hydrolysis by 0.1 M HCl at 80°C. Oligomers containing a single glucuronic acid (GlcA) moiety in addition to n(≥ 2) repeats of the dimer →4)-α-D-GalpA-(1→2)-α-LRhap-(1→ were isolated from the hydrolysate by ion-exchange and gel-permeation. Glycosyl linkage composition analysis and 1H NMR studies indicated that the GlcA was attached to O-3 of a galacturonic acid (GalA) residue, as shown for the two pentamers β-D-GlcpA-(1→)-α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-α-DGalpA-(1→2)-L-Rhap and α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-[β-D-GlcpA-(1→3)]-α-D-GalpA-(1→2)-L-Rhap. Substitution by GlcA was estimated as occurring on one Gala residue out of 72 in the rhamnogalacturonan fraction of the backbone of beet pectins.

glucuronic acid, sugar beet, rhamnogalacturonan, pectin

13C NMR data:
missing...
1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
2,4,2,3	bDGlcpA	4.72	3.41	3.54	3.54	3.75	-
2,4,2	aDGalpA	5.04	4.00	4.13	4.54	4.62	-
2,4	aLRhap	5.30	4.13	3.89	3.43	3.80	1.26
2	aDGalpA	5.07-5.16	3.93-3.99	4.12-4.14	4.44-4.45	4.60	-
	?LRhap	4.92-5.23	3.97-4.05	3.64-3.89	3.36-3.47	3.41-3.81	1.28-1.30

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C[C@@H]1OC(O)[C@H](O[C@H]2O[C@H](C(=O)O)[C@H](O[C@@H]3O[C@@H](C)[C@H](O)[C@@H](O)[C@H]3O[C@H]3O[C@H](C(=O)O)[C@H](O)[C@H](O[C@@H]4O[C@H](C(=O)O)[C@@H](O)[C@H](O)[C@H]4O)[C@H]3O)[C@H](O)[C@H]2O)[C@H](O)[C@H]1O

838.671 g/mol (C₃₀H₄₆O₂₇)

Sugar-beet pulp was de-esterified and submitted to 72 h hydrolysis by 0.1 M HCl at 80°C. Oligomers containing a single glucuronic acid (GlcA) moiety in addition to n(≥ 2) repeats of the dimer →4)-α-D-GalpA-(1→2)-α-LRhap-(1→ were isolated from the hydrolysate by ion-exchange and gel-permeation. Glycosyl linkage composition analysis and 1H NMR studies indicated that the GlcA was attached to O-3 of a galacturonic acid (GalA) residue, as shown for the two pentamers β-D-GlcpA-(1→)-α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-α-DGalpA-(1→2)-L-Rhap and α-D-GalpA-(1→2)-α-L-Rhap-(1→4)-[β-D-GlcpA-(1→3)]-α-D-GalpA-(1→2)-L-Rhap. Substitution by GlcA was estimated as occurring on one Gala residue out of 72 in the rhamnogalacturonan fraction of the backbone of beet pectins.

glucuronic acid, sugar beet, rhamnogalacturonan, pectin

13C NMR data:
missing...
1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
2,3	bDGlcpA	4.72-4.75	3.45	3.57	3.57	3.71	-
2,4,2	aDGalpA	5.08	3.86	3.97	4.30	4.62	-
2,4	aLRhap	5.41	4.11	3.90	3.41	3.78	1.24
2	aDGalpA	5.07-5.16	4.09-4.13	4.25-4.27	4.60	4.64	-
	?LRhap	4.92-5.24	3.98-4.08	3.64-3.87	3.37-3.51	3.40-3.87	1.29-1.31

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C[C@@H]1OC(O)[C@H](O[C@H]2O[C@H](C(=O)O)[C@H](O[C@@H]3O[C@@H](C)[C@H](O)[C@@H](O)[C@H]3O[C@H]3O[C@H](C(=O)O)[C@H](O)[C@H](O)[C@H]3O)[C@H](O[C@@H]3O[C@H](C(=O)O)[C@@H](O)[C@H](O)[C@H]3O)[C@H]2O)[C@H](O)[C@H]1O

838.671 g/mol (C₃₀H₄₆O₂₇)