Yu J, Yu D W, Checkla D M, Freedberg I M, Bertolino A P
Ronald O. Perelman Department of Dermatology, N.Y.U. Medical Center, N.Y. 10016.
J Invest Dermatol. 1993 Jul;101(1 Suppl):56S-59S. doi: 10.1111/1523-1747.ep12362635.
Human hair keratins were among the first to be studied but it is only recently that sufficient information has been obtained to gain a basic biologic perspective of these proteins. Hair keratins are members of the intermediate filament family of proteins, yet are sufficiently divergent from epidermal keratins to warrant separate classification: type Ia and IIa ("hard"/hair keratins) and type Ib and IIb (epidermal and other "soft" keratins). As with hair keratins from other species, the human proteins may be distinguished from their epidermal counterparts by a relatively higher cysteine content, 7.6% versus 2.9%, respectively. This feature reflects utilization of disulfide bonding in producing a tougher, more durable structure in the tissues in which the hair keratins are distributed. Although prominent in hair, their distribution is not strictly limited to this tissue. A number of molecular characteristics have been elucidated from human hair keratin gene studies including amino acid sequence data for a type Ia hair keratin. Studies of various pedigrees has revealed a fairly wide latitude of variation in human hair keratin expression that is tolerated without associated obvious hair phenotypic change. Thus, a foundation of knowledge regarding these proteins has emerged and continues to evolve.
人类毛发角蛋白是最早被研究的角蛋白之一，但直到最近才获得了足够的信息，从而能够从基本生物学角度了解这些蛋白质。毛发角蛋白是中间丝蛋白家族的成员，但与表皮角蛋白有足够大的差异，因此需要单独分类：Ia型和IIa型（“硬”/毛发角蛋白）以及Ib型和IIb型（表皮和其他“软”角蛋白）。与来自其他物种的毛发角蛋白一样，人类毛发角蛋白与表皮角蛋白的区别在于其半胱氨酸含量相对较高，分别为7.6%和2.9%。这一特征反映了二硫键在毛发角蛋白分布的组织中形成更坚韧、更耐用结构方面的作用。尽管毛发角蛋白在毛发中含量丰富，但其分布并不严格局限于该组织。从人类毛发角蛋白基因研究中已经阐明了许多分子特征，包括一种Ia型毛发角蛋白的氨基酸序列数据。对不同家系的研究表明，人类毛发角蛋白表达存在相当大的变异范围，这种变异在没有明显毛发表型变化的情况下也能被耐受。因此，关于这些蛋白质的知识基础已经形成并不断发展。
