Glycosaminoglycan conformations and changes on periodate oxidation.
Glycosaminoglycan conformations and changes on periodate oxidation.
复制标题
糖胺聚糖构象和高碘酸盐氧化的变化。
DOI：
10.1002/bip.360281106
复制
发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
Chakrabarti,B
中科院分区：
文献类型：
--
作者：
Ueno,N;Chakrabarti,B
采用尺寸排阻色谱柱，通过CD和高效液相色谱法（HPLC）监测糖胺聚糖（GAG）（包括透明质酸盐（HA）、软骨素（CH）（软骨素、4-硫酸软骨素和6-硫酸软骨素）、硫酸皮肤素（DS）和硫酸角质素（KS））的进行性高碘酸盐氧化。还使用一级和二级动力学测量和计算了氧化速率，数据似乎与一级动力学拟合得更好。在HA和CH中，氧化后208 nm处的- π* 酰胺谱带强度降低，但在HA中，高碘酸盐处理16 h后其变为阳性。在CH中，谱带消失，并且200 nm以下的π - π* 酰胺谱带变为光学活性的。同时，这两种氧化GAG在290 nm附近出现第二个阴性条带。氧化导致DS的CD发生轻微变化。它通常在210 nm处显示非常弱的n- π* 带，但在190 nm附近显示强烈的π - π* 酰胺带。KS的CD不受高碘酸盐的影响。然而，动力学研究表明，DS的氧化速率高于HA和CH。除KS外，所有其他氧化聚合物在HPLC分析中均显示分子量明显降低（峰保留时间更长）。CD和HPLC结果均归因于HA和CH的主要构象变化以及DS的次要构象变化。高碘酸盐氧化的难易程度和程度以及高碘酸盐处理后分子性质的变化主要取决于高碘酸盐处理后分子性质的变化，而不是氧化速率。HA和CH之间的构象变化存在明显差异，如它们的二向色性行为所表明的，这归因于HA中C-4羟基的赤道配置和CH的轴向配置。
The progressive periodate oxidation of glycosaminoglycans (GAG), including hyaluronate (HA), chondroitins (CH) (chondroitin, chondroitin 4‐ and 6‐sulfate), dermatan sulfate (DS), and keratan sulfate (KS), were monitored by CD and high performance liquid chromatography (HPLC) using a size‐exclusion column. The rate of oxidation also was measured and calculated using first‐ and second‐order kinetics, and the data appear to fit better with first‐order kinetics. In both HA and CH, then– π* amide band at 208 nm decreases in intensity upon oxidation, but in HA it becomes positive after 16 h of periodate treatment. In CH, the band disappears, and the π – π* amide band below 200 nm becomes optically active. Concomitantly, a second negative band near 290 nm appears for these two oxidized GAG. Oxidation causes a slight change in the CD of DS. It ordinarily displays a very weakn– π* band at 210 nm, but instead shows an intense π – π* amide band near 190 nm. CD of KS remains unaffected by periodate. Kinetic studies, however, show a higher oxidation rate for DS than HA and CH. With the exception of KS, all other oxidized polymers shown an apparent decrease in molecular weight (higher peak retention time) in HPLC analysis. Both CD and HPLC results have been attributed to a major conformational cahange of HA and CH, and a minor one for DS. The ease and extent of periodate oxidation as well as the changes in molecular properties following periodate treatmenat are critically dependent on the changes in molecular properties following periodate treatment are critically dependent on the configuration of the individual GAG rather than the oxidation rate. There is a distinct difference in the conformational change between HA and CH, as manifested by their dichroic behavior, that was attributed to the equatorial disposition of C‐4 hydroxyl group in HA and axial disposition CH.