Mosher D F
Biochim Biophys Acta. 1977 Mar 28;491(1):205-10. doi: 10.1016/0005-2795(77)90056-3.
Incubation of cultured human fibroblasts with blood coagulation factor XIIIa (plasma transglutaminase, fibrinoligase) and the fluorescent primary amine, N-(5-aminopentyl)-5-dimethylaminonaphthalene-1-sulfonamide, resulted in fluorescent labeling of three cellular polypeptides. The molecular weights of the labeled polypeptides, estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate after reduction, were: greater than 1.2-10(6), 2.2-10(5), and 1.3-10(5). The labeled 2.2-10(5) dalton polypeptide was susceptible to mild trypsinization and not present in cultures of SV-40 transformed fibroblasts, indicating that it is the subunit of cell-surface fibronectin and identical with the external transformation-sensitive polypeptide of similar molecular weight described by others. Upon coelectrophoresis, the labeled 2.2-10(5) dalton polypeptide migrated slightly behind the subunit of plasma fibronectin (cold-insoluble globulin), indicating that the immunologically cross-reactive forms of fibronectin in human plasma and cultured human fibroblasts differ slightly in molecular weight. The identities of the labeled greater than 1.2-10(6) and 1.3-10(5) dalton polypeptides are not known. The XIIa-reactive glutamine residues of fibroblast cell-surface proteins are potential sites for intermolecular cross-linking (by xi-(gamma-glutamyl)lysyl linkages) to other proteins of connective tissue.
将培养的人成纤维细胞与凝血因子XIIIa（血浆转谷氨酰胺酶、纤维蛋白连接酶）及荧光伯胺N-(5-氨基戊基)-5-二甲基氨基萘-1-磺酰胺一起孵育，结果三种细胞多肽被荧光标记。经还原后在十二烷基硫酸钠中进行聚丙烯酰胺凝胶电泳估计，标记多肽的分子量分别为：大于1.2×10⁶、2.2×10⁵和1.3×10⁵。标记的2.2×10⁵道尔顿多肽易被轻度胰蛋白酶消化，且不存在于SV-40转化的成纤维细胞培养物中，这表明它是细胞表面纤连蛋白的亚基，与其他人描述的分子量相似的外部转化敏感多肽相同。在共电泳时，标记的2.2×10⁵道尔顿多肽迁移到血浆纤连蛋白（冷不溶性球蛋白）亚基的稍后方，这表明人血浆和培养的人成纤维细胞中纤连蛋白的免疫交叉反应形式在分子量上略有不同。标记的大于1.2×10⁶和1.3×10⁵道尔顿多肽的身份尚不清楚。成纤维细胞表面蛋白的XIIIa反应性谷氨酰胺残基是与结缔组织其他蛋白进行分子间交联（通过ε-(γ-谷氨酰)赖氨酰键）的潜在位点。
