Isles M, Foweraker A R, Jennings B R, Hardingham T, Muir H
Biochem J. 1978 Jul 1;173(1):237-43. doi: 10.1042/bj1730237.
An electric field causes partial alignment of macromolecules in a dilute solution. The accompanying changes in the solution birefringence offer a sensitive and quick means of monitoring the rates of particle orientation and hence the size of the solute molecules. Such measurements are reported for dilute solutions of proteoglycans in the absence and presence of added hyaluronic acid. The proteoglycan molecules are shown to be some 580 nm long. In the presence of hyaluronic acid they form aggregates that appear to be consistent with the model previously proposed in which the proteoglycans attach radially to the extended hyaluronic acid chain. The electric-birefringence relaxation rates indicate aggregates of similar length to that of the extended hyaluronic acid chain, with the proteoglycans spaced on average at 29nm intervals. A proteoglycan sample the cystine residues of which had been reduced and alkylated showed no evidence of aggregation with hyaluronic acid up to the concentrations of the acid corresponding to 1% of the total uronic acid content. The electric-birefringence method is shown to have a large potential in the study of associating polysaccharide solutions.
电场会使稀溶液中的大分子发生部分排列。溶液双折射随之发生的变化提供了一种灵敏且快速的手段，可用于监测粒子取向速率，进而测定溶质分子的大小。本文报道了在不存在和存在添加的透明质酸的情况下，蛋白聚糖稀溶液的此类测量结果。结果表明，蛋白聚糖分子长度约为580纳米。在透明质酸存在的情况下，它们会形成聚集体，这似乎与先前提出的模型一致，即蛋白聚糖径向附着于伸展的透明质酸链上。电场双折射弛豫速率表明，聚集体的长度与伸展的透明质酸链相似，蛋白聚糖平均间距为29纳米。一个胱氨酸残基已被还原和烷基化的蛋白聚糖样品，在酸浓度达到总糖醛酸含量的1%之前，均未显示出与透明质酸发生聚集的迹象。结果表明，电场双折射方法在研究缔合多糖溶液方面具有很大潜力。
