Table 1.
Ratios of peak height of sulfated/unsulfated residues at A-6, A-2, and I-2 for Hp and by-products. 2-O sulfation of iduronic acid is most clearly identifiable by the chemical shift of carbon 1 at 102 ppm.
| Carbon Sample | A6 (69 ppm) | A2 (57 ppm) | I1 (102 ppm) |
|---|---|---|---|
| Sulfated/unsulfated | |||
| Hp | 3 | 2.7 | 2.6 |
| A | 0.7 | 0.8 | 0.9 |
| B | 0.9 | 1.3 | 0.7 |
| C | 0.7 | 0.7 | 0.8 |
| D | 0.7 | 1.3 | 0.7 |
N and 6-O sulfation are best identified by changes in signal of carbon 2 and 6 of N-acetylglucosamine at 57 and 69 ppm, respectively. 6-O-sulfation in glucosamine (evident in the 13C NMR spectrum at 69 ppm) is referred to as ‘A6’, N-sulfation in glucosamine (58 ppm) as ‘A2’ and 2-O-sulfation (monitored by the signal for C-1 in iduronate residues (102 ppm) as ‘I1’.