Soltés Ladislav, Stankovská Monika, Brezová Vlasta, Schiller Juergen, Arnhold Juergen, Kogan Grigorij, Gemeiner Peter
Institute of Experimental Pharmacology, Slovak Academy of Sciences, SK-84104 Bratislava, Slovakia.
Carbohydr Res. 2006 Dec 11;341(17):2826-34. doi: 10.1016/j.carres.2006.09.019. Epub 2006 Oct 17.
The degradation of high-molar-mass hyaluronan (HA) by copper(II) chloride and ascorbate was studied by means of rotational viscometry. It was found that even small amounts of CuCl(2) present in the oxidative system led to the pronounced degradation of HA, reflected in a rapid decrease of the dynamic viscosity of the biopolymer solution. Such degradation was induced by free radicals generated in elevated amounts in the presence of copper ions. Electron paramagnetic resonance investigations performed on a model oxidative system containing Cu(II) and ascorbic acid proved the formation of relatively stable ascorbate anion radicals resulting from the reaction of ascorbic acid with hydroxyl radicals. In this way, by scavenging the hydroxyl radicals, ascorbic acid protected HA from their degradative action. Matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry was applied to analyze the degraded HA. The results showed that only regular fragmentation of hyaluronan occurred using the mentioned oxidative system that led to the formation of HA oligomers with unaffected primary chemical structure.
通过旋转粘度测定法研究了氯化铜（II）和抗坏血酸盐对高摩尔质量透明质酸（HA）的降解作用。研究发现，即使氧化体系中存在少量的CuCl₂也会导致HA显著降解，这表现为生物聚合物溶液的动态粘度迅速降低。这种降解是由铜离子存在时大量产生的自由基引起的。对含有Cu（II）和抗坏血酸的模型氧化体系进行的电子顺磁共振研究证明，抗坏血酸与羟基自由基反应生成了相对稳定的抗坏血酸阴离子自由基。通过这种方式，抗坏血酸通过清除羟基自由基，保护HA免受其降解作用。采用基质辅助激光解吸电离飞行时间（MALDI-TOF）质谱法分析降解后的HA。结果表明，使用上述氧化体系时，透明质酸仅发生规则断裂，形成了一级化学结构未受影响的HA低聚物。
