DILUTE-SOLUTION PROPERTIES OF PROTEOGLYCAN FRACTIONS FROM BOVINE NASAL CARTILAGE
DILUTE-SOLUTION PROPERTIES OF PROTEOGLYCAN FRACTIONS FROM BOVINE NASAL CARTILAGE
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DOI：
10.1002/bip.1978.360170316
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发表时间：
1978-01-01
期刊：
影响因子：
2.9
通讯作者：
CLELAND, RL
中科院分区：
文献类型：
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作者：
KITCHEN, RG;CLELAND, RL
通过光散射，从解离密度梯度最致密部分分离的新鲜蛋白多糖（成年牛鼻软骨）在 4 M 盐酸胍 (GdnHCl) 中的重均分子量约为 106。通过用4M GdnHCl从2%琼脂糖凝胶（正常的和交联的）洗脱获得的这种材料的级分具有0.8至2.6倍的蛋白聚糖亚基MW。 106 和均方根半径范围为 35-52 nm，在相同溶剂中。每个蛋白多糖亚基的蛋白质MW约为1.2倍。 105，硫酸角质素的约1.8倍。 105，两者都与总分子量无关。使用具有硫酸软骨素（40个二糖）和硫酸角质素（15个二糖）的均匀侧链以及无规卷曲多肽主链的随机飞行接枝共聚物模型来估计未受扰动的半径，对于1.5倍的MW，其约为19nm。 106. 级分的实验光散射数据与线性和适当支化聚合物的颗粒散射因子的理论曲线非常吻合。基于支化聚合物模型的扰动计算对线圈膨胀的检查表明，膨胀并没有根据模型计算的未扰动半径来解释实验观察到的半径。一种可能的解释是，由于侧链簇的取代，多肽链的局部显着硬化增加了未受干扰的半径。特性粘度[η]为4 M GdnHCl，范围为120-180 ml/g，并且可以用等效球模型来解释；对于柔性线性聚合物，弗洛里数大约具有其正常值。该模型对沉降系数的处理不太成功，因为 Mandelkern-Flory 参数 β。明显随着MW的增加而增加；平均值与柔性线性聚合物的平均值相似，但 β 的变化较大。使得该方法仅适用于粗略估计蛋白多糖的分子量。纯化的蛋白多糖在 0.2 M NaCl 中的 MW 与在 4 M GdnHCl 中的相同，而粗制剂在 0.2 M NaCl 中的 MW 更高，这可能是由于连接蛋白去除不完全而导致的缔合。
Fresh proteoglycans (adult bovine nasal cartilage) isolated from the densest portion of a dissociative density gradient had a weight-average MW of about 106 in 4 M guanidine hydrochloride (GdnHCl) by light scattering. Fractions of such material obtained by elution with 4 M GdnHCl from 2% agarose gel, both normal and cross-linked, had proteoglycan subunit MW ranging from 0.8 to 2.6 .times. 106 and root-mean-square radii ranging 35-52 nm in the same solvent. The protein MW per proteoglycan subunit was about 1.2 .times. 105 and that of keratan sulfate about 1.8 .times. 105, both independent of total molecular weight. A random-flight graft copolymer model having uniform side chains of chondroitin sulfate (40 disaccharides) and keratan sulfate (15 disaccharides) and a random-coil polypeptide backbone was used to estimate the unperturbed radius, which was about 19 nm for a MW of 1.5 .times. 106. Experimental light-scattering data for fractions were fitted very well by theoretical curves for the particle scattering factor for both linear and appropriate branched polymers. Examination of coil expansion on the basis of perturbation calculations for branched polymer models suggested that expansion did not account for the experimentally observed radii in terms of unperturbed radii calculated from the model. A possible explanation is that substantial local stiffening of the polypeptide chain due to substitution of side-chain clusters increases the unperturbed radii. The intrinsic viscosity [.eta.] is 4 M GdnHCl ranged 120-180 ml/g, and could be interpreted in terms of the equivalent sphere model; the Flory number has approximately its normal value for flexible linear polymers. The treatment of the sedimentation coefficient by this model is less successful, since the Mandelkern-Flory parameter .beta. apparently increases with increasing MW; average values are similar to those for flexible linear polymers, but the variation in .beta. makes this method useful only for rough estimation of MW of proteoglycans. MW of purified proteoglycans are the same in 0.2 M NaCl as in 4 M GdnHCl, while crude preparations gave higher MW in 0.2 M NaCl, probably because of association due to incomplete removal of linking proteins.