TABLE 4.
1H NMR spectra of HGMB, GSH, isoprene monoxide, and 1-hydroxy-2-methyl-3-butenea
| H | Chemical shift (intensity, multiplicity)
|
||||
|---|---|---|---|---|---|
| HGMB
|
GSH | Isoprene monoxide | 1-Hydroxy-2-methyl-3-butene | ||
| Racemic | AD45 | ||||
| Glutamate | |||||
| Hα | 3.45 (1, NR) | 3.5 (1, NR) | 3.6 (1, dd) | ||
| Hβ | 1.9 (2, m) | 2.0 (2, m) | 1.9 (2, m) | ||
| Hγ | 2.3 (2, m) | 2.4 (2, m) | 2.3 (2, m) | ||
| Cysteine | |||||
| Hα | 4.35 (1, m) | 4.4 (1, m) | 4.35 (1, d) | ||
| Hβ | 2.65 (1, m)b | 2.70 (1, m) | 2.70 (1, d) | ||
| Hβ′ | 2.80 (1, m) | 2.85 (1, m) | 2.75 (1, d) | ||
| Glycine | |||||
| Hα | 3.55 (1, s)b | 3.6 (2, s)b | 3.6 (2, s) | ||
| Isoprene moiety | |||||
| Ha | 3.451) (NR) | 3.5 (2, NR) | 2.8 (2, dd) | 3.3 (2, dd) | |
| Hb | 2.1 (1, m) | ||||
| Hc | 5.65 (1, dd) | 5.7 (1, dd) | 5.6 (1, m) | 5.6 (1, m) | |
| Hd | 5.05 (1, dd) | 5.1 (2, dd) | 5.3 (2, m) | 4.9 (2, m) | |
| Hme | 1.15 (1.5, s) | 1.2 (0.4, s) | 1.3 (3, s) | 0.8 (3, d) | |
| 1.20 (1.5, s) | 1.25 (2.6, s) | ||||
a
Spectra were recorded in D2O at room temperature. Chemical shifts were measured relative to sodium 4,4-dimethyl-4-silapentane-1-sulfonate and assigned with 0.05-ppm accuracy. The protons are assigned with reference to Fig. 5. NR, not resolved. Multiplicity of the Hα (Glu), and Ha (isoprene moiety) protons could not be resolved due to overlap of spectral lines.
b
Singlet Hα (Gly) protons gave two signals due to an increased rotational barrier in the conjugate compared to unmodified GSH.