Peterson L L, Zettergren J G, Wuepper K D
J Invest Dermatol. 1983 Jul;81(1 Suppl):95s-100s. doi: 10.1111/1523-1747.ep12540777.
Transglutaminase is a calcium-dependent enzyme found widely in nature. It catalyzes the formation of epsilon-(gamma-glutamyl)lysine bonds that participate in processes varying from fibrin clot formation to epidermal cell envelope formation. Epidermal transglutaminase is localized to the granular layer of the epidermis. It catalyzes the covalent cross-linking of a soluble cytoplasmic substrate into large polymers to form the cornified envelope that lines the inner membrane of keratinocytes in the stratum corneum. The soluble precursor from epidermis has been named keratolinin, and from keratinocyte culture, it has been named involucrin. Hair follicle transglutaminase is biochemically and immunochemically distinct from its epidermal counterpart. It has been localized to the inner root sheath and medulla of the hair follicle. The substrate of hair follicle transglutaminase has been poorly defined but appears to be rich in the amino acid citrulline. Transglutaminase has been shown to be an important marker of normal differentiation. There is a rise in its activity at the time of keratinization, and transglutaminase activity has been shown to be greatly decreased in basal cell epithelioma and in psoriasis. Keratinocyte cell culture has proven most helpful in delineating the processes of normal differentiation and keratinization, since the formation of the cell envelope in culture appears to parallel the formation in vivo.
转谷氨酰胺酶是一种在自然界中广泛存在的钙依赖性酶。它催化ε-（γ-谷氨酰基）赖氨酸键的形成，这些键参与从纤维蛋白凝块形成到表皮细胞包膜形成等多种过程。表皮转谷氨酰胺酶定位于表皮的颗粒层。它催化一种可溶性细胞质底物共价交联形成大聚合物，以形成位于角质层角质形成细胞内膜内的角化包膜。来自表皮的可溶性前体被命名为角蛋白原，来自角质形成细胞培养物的则被命名为内披蛋白。毛囊转谷氨酰胺酶在生化和免疫化学上与其表皮对应物不同。它定位于毛囊的内根鞘和髓质。毛囊转谷氨酰胺酶的底物定义尚不明确，但似乎富含氨基酸瓜氨酸。转谷氨酰胺酶已被证明是正常分化的重要标志物。在角质化时其活性会升高，并且已表明在基底细胞上皮瘤和银屑病中转谷氨酰胺酶活性会大大降低。角质形成细胞培养已被证明在描绘正常分化和角质化过程中最有帮助，因为培养物中细胞包膜的形成似乎与体内形成过程相似。
