Comper W D, Lyons K C
Biochemistry Department, Monash University, Clayton, Victoria, Australia.
Biochem J. 1993 Jan 15;289 ( Pt 2)(Pt 2):543-7. doi: 10.1042/bj2890543.
The hydrodynamic frictional resistance to water flow exerted by articular cartilage proteoglycan is shown to be similar to that of proteoglycan isolated from Swarm rat chondrosarcoma, and independent of the state of aggregation of the proteoglycan. Frictional resistance is dependent, however, on the chain segments of the constituent chondroitin-sulphate and keratan-sulphate chains of the proteoglycan. Frictional resistance offered by chondroitin sulphate was independent of pH over the range 3.2-8.7. This confirms previous studies, associated with varying ionic strength and chemical modification of ionic groups of chondroitin sulphate, which showed that the frictional resistance offered by this molecule is independent of electrostatic factors. Water-structure-breaking and hydrogen-bond-breaking solvents were also without major effects on the flow resistance offered by chondroitin sulphate. An overall secondary structure of chondroitin sulphate was not evident, as it showed no significant difference to dextran in terms of its temperature dependence of relative viscosity. Local regions of rigid secondary structure, as manifested through inter-residue hydrogen bonding between sugar residues, is likely to control flow resistance as periodate-oxidized chondroitin sulphate and periodate-oxidized and reduced preparations showed a significant decrease in their frictional resistance to water.
研究表明，关节软骨蛋白聚糖对水流的流体动力摩擦阻力与从斯旺大鼠软骨肉瘤中分离出的蛋白聚糖相似，且与蛋白聚糖的聚集状态无关。然而，摩擦阻力取决于蛋白聚糖中组成成分硫酸软骨素和硫酸角质素链的链段。硫酸软骨素提供的摩擦阻力在pH值3.2至8.7范围内与pH无关。这证实了先前的研究，这些研究涉及不同的离子强度以及硫酸软骨素离子基团的化学修饰，结果表明该分子提供的摩擦阻力与静电因素无关。破坏水结构和氢键的溶剂对硫酸软骨素提供的流动阻力也没有重大影响。硫酸软骨素的整体二级结构不明显，因为其相对粘度的温度依赖性与右旋糖酐相比没有显著差异。通过糖残基之间的残基间氢键表现出的局部刚性二级结构区域可能控制流动阻力，因为高碘酸盐氧化的硫酸软骨素以及高碘酸盐氧化和还原的制剂对水的摩擦阻力显著降低。
