Yates E A, Santini F, De Cristofano B, Payre N, Cosentino C, Guerrini M, Naggi A, Torri G, Hricovini M
Istituto di Chimica e Biochimica G. Ronzoni, Milan, Italy.
Carbohydr Res. 2000 Oct 20;329(1):239-47. doi: 10.1016/s0008-6215(00)00144-0.
1H, 13C NMR chemical shifts and 1J(CH) coupling constants were measured for derivatives of heparin containing various sulfation patterns. 1H and 13C chemical shifts varied considerably after introducing electronegative sulfate groups. Chemical shifts of protons linked to carbons changed by up to 1 ppm on substitution with O- and N-sulfate or acetyl groups. Differences up to 10 ppm were detected for 13C chemical shifts in substituted glucosamine, but a less clear dependence was found in iduronate. 1J(CH) values formed two groups, corresponding to either sulfation or non-sulfation at positions 2 and 3 of glucosamine. O-sulfation caused increases up to 6 Hz in 1J(CH) and N-sulfation decreases up to 4 Hz. N-acetylation gave similar 1J(CH) values to N-sulfation. At positions 2 and 3 of iduronate the trend was less marked; 1J(CH) for O-sulfated positions usually increasing. Introduction of sulfate groups influences chemical shift and 1J(CH) values at the position of substitution, but also at more remote positions. 1J(CH) at the glycosidic linkage positions varied between free-amino and N-sulfated compounds, by up to 9 Hz. These results and changes in chemical shift values suggest that iduronate residues and the glycosidic linkages are affected, indicating overall conformational change. This may have important implications for biological activities.
对含有各种硫酸化模式的肝素衍生物测量了¹H、¹³C核磁共振化学位移和¹J(CH)耦合常数。引入电负性硫酸基团后，¹H和¹³C化学位移有很大变化。与碳相连的质子的化学位移在被O-硫酸酯、N-硫酸酯或乙酰基取代时变化高达1 ppm。在取代的葡糖胺中检测到¹³C化学位移的差异高达10 ppm，但在艾杜糖醛酸中发现的相关性不太明显。¹J(CH)值形成两组，分别对应于葡糖胺2位和3位的硫酸化或非硫酸化。O-硫酸化使¹J(CH)增加高达6 Hz，N-硫酸化使¹J(CH)降低高达4 Hz。N-乙酰化给出的¹J(CH)值与N-硫酸化相似。在艾杜糖醛酸的2位和3位，这种趋势不太明显；O-硫酸化位置的¹J(CH)通常增加。硫酸基团的引入不仅影响取代位置的化学位移和¹J(CH)值，还影响更远的位置。游离氨基和N-硫酸化化合物之间糖苷键位置的¹J(CH)变化高达9 Hz。这些结果和化学位移值的变化表明艾杜糖醛酸残基和糖苷键受到影响，表明整体构象发生了变化。这可能对生物活性有重要影响。
