Seyer J M, Hutcheson E T, Kang A H
J Clin Invest. 1977 Feb;59(2):241-8. doi: 10.1172/JCI108634.
Collagens in normal human liver and in alcoholic cirrhotic liver were investigated. Collagens were solubilized by limited proteolysis with pepsin under nondenaturing conditions, and after purification, were fractionated into types I and III by selective precipitation with NaCl. After carboxymethyl cellulose and agarose chromatography, the resulting alpha-chains from each of the collagen types were analyzed with respect to their amino acid and carbohydrate compositions. A comparison of the results obtained from normal liver with those from the diseases organ revealed no significant differences. The isolated human liver alpha1(I) and alpha1(III) chains were digested with CNBr and the generated peptides were separated and purified by a combination of ion-exchange and molecular sieve chromatography. The molecular weight and the amino acid and the carbohydrate compositions of each of the peptides were identical to those of the corresponding human skin peptides except for the slightly higher content of hydroxylysine in some of the peptides. The relative content of type III in relation to type I collagen in both normal anc cirrhotic liver was determined by digesting washed liver homogenates directly with CNBr and quantitating the resultant alpha1(I) and alpha 1(III) peptides after chromatographic separation. The relative quantities of these peptides indicated that normal human liver contained an average of 47% type III, with the remainder being type I. Cirrhotic liver, on the other hand, contained a significantly smaller proportion of type III, ranging from 18 to 34% in different samples, with a corresponding increase in type I. These findings indicate that although the amino acid and carbohydrate compositions of collagens deposited in cirrhotic liver are normal, the fibrotic process of alcoholic liver disease in humans is accompanied by an alteration in tissue collagen polymorphism, and suggest that the observed alterations may have pathogenetic implications.
对正常人肝脏和酒精性肝硬化肝脏中的胶原蛋白进行了研究。在非变性条件下，用胃蛋白酶进行有限的蛋白水解使胶原蛋白溶解，纯化后，通过用氯化钠选择性沉淀将其分离为I型和III型。经过羧甲基纤维素和琼脂糖色谱分析后，对每种胶原蛋白类型产生的α链进行氨基酸和碳水化合物组成分析。将正常肝脏的结果与患病器官的结果进行比较，未发现显著差异。将分离得到的人肝脏α1(I)和α1(III)链用溴化氰消化，产生的肽通过离子交换和分子筛色谱相结合的方法进行分离和纯化。除了某些肽中羟赖氨酸含量略高外，每种肽的分子量、氨基酸和碳水化合物组成与相应的人皮肤肽相同。通过直接用溴化氰消化洗涤过的肝脏匀浆，并在色谱分离后对所得α1(I)和α1(III)肽进行定量，测定正常和肝硬化肝脏中III型相对于I型胶原蛋白的相对含量。这些肽的相对量表明，正常人肝脏平均含有47%的III型，其余为I型。另一方面，肝硬化肝脏中III型的比例明显较小，不同样本中为18%至34%，I型相应增加。这些发现表明，虽然沉积在肝硬化肝脏中的胶原蛋白的氨基酸和碳水化合物组成正常，但人类酒精性肝病的纤维化过程伴随着组织胶原蛋白多态性的改变，并表明观察到的改变可能具有致病意义。
