Hunter L, Skerrow D
Biochim Biophys Acta. 1982 Jan 12;714(1):164-9. doi: 10.1016/0304-4165(82)90139-8.
Psoriatic epidermis has a rapid rate of turnover and produces a stratum corneum with an abnormal tonofilament composition. One polypeptide chain, (Mr 70,000) is absent or greatly decreased in relative amount and two other chains, (Mr 63,000 and 55,000), which are normally modified in the living cells, persists into the stratum corneum. Increasing the turnover of normal epidermis has been shown to cause the persistence of 63 and 55 kilodalton chains in the stratum corneum but does not affect the relative amount of 70 kilodalton chain. It has, therefore, been suggested that, in psoriasis, the deficiency of the 70 kilodalton chain may occur prior to or simultaneously with the induction of increased tissue turnover. In the present study, the polypeptide chain composition of living psoriatic epidermis has been examined. It is shown that the relative amounts of 70 kilodalton chain in psoriatic stratum corneum and involved living epidermis from the same site are not significantly different. The abnormality is, therefore, already present in the living cells and it appears that, in psoriasis, the synthesis of the 70 kilodalton chain is defective. The uninvolved epidermis of psoriatics is intermediate between normal and involved psoriatic epidermis both in the ability to synthesise the 70 kilodalton chain and to modify the 63 and 55 kilodalton chains. Comparisons of amino acid compositions of proteins containing different proportions of 70 kilodalton chain suggest that it has a considerably higher content of glycine and serine than the other tonofilament chains. These studies suggest that the 70 kilodalton chain may be functionally different from the other tonofilament chains. The defect in its synthesis in psoriasis is a relatively early event and may be involved with the induction of increased tissue turnover or induced by the same abnormal conditions as the increased tissue turnover.
银屑病表皮的更新速度很快，产生的角质层具有异常的张力丝组成。一种多肽链（分子量70,000）缺失或相对含量大幅降低，另外两条链（分子量63,000和55,000），它们在活细胞中通常会被修饰，却持续存在于角质层中。已表明增加正常表皮的更新会导致角质层中63和55千道尔顿链的持续存在，但不影响70千道尔顿链的相对含量。因此，有人提出，在银屑病中，70千道尔顿链的缺乏可能在组织更新增加的诱导之前或同时发生。在本研究中，已对活的银屑病表皮的多肽链组成进行了检查。结果表明，来自同一部位的银屑病角质层和受累活表皮中70千道尔顿链的相对含量没有显著差异。因此，这种异常已经存在于活细胞中，并且在银屑病中，70千道尔顿链的合成似乎存在缺陷。银屑病患者未受累的表皮在合成70千道尔顿链以及修饰63和55千道尔顿链的能力方面介于正常表皮和受累的银屑病表皮之间。对含有不同比例70千道尔顿链的蛋白质的氨基酸组成进行比较表明，它的甘氨酸和丝氨酸含量比其他张力丝链高得多。这些研究表明，70千道尔顿链在功能上可能与其他张力丝链不同。其在银屑病中合成的缺陷是一个相对早期的事件，可能与组织更新增加的诱导有关，或者由与组织更新增加相同的异常情况所诱导。
