Keratin additives

Component of the myelin sheath surrounding the axons of nerve cells. Additional compounds of the myelin sheath are phospholipids, cholesterol, cerebrosides, and specific keratins. The myelin sheath constitutes an isolating barrier during electrophysiological axonal signaling. 

This section summarizes the current information about different human keratins, their functional significance, cell-type-specific distribution as well as their coexpression with myoepithelial markers and estrogen receptor alpha (ER), because these markers exhibit characteristic expression patterns in some human breast tumors. In many of these cases, a definite diagnosis can be achieved only when additional information is provided by immunohistochemistry. 

K7/K19 secondary keratins Apart from K8/K18, type II keratin K7 and type I K19 are additional (secondary) and also widely distributed glandular keratins... 

Urea increases the water content of the stratum corneum, presumably as a result of the hygroscopic characteristics of this naturally occurring molecule. Urea is also keratolytic. The mechanism of action appears to involve alterations in prekeratin and keratin, leading to increased solubilization. In addition, urea may break hydrogen bonds that keep the stratum... 

In the tanning process hides are first washed or soaked, hair and keratinous debris are removed, bated (enzymes are used to break down non-collagenous components, which are washed out) and the hide is acid-pickled to prepare for the addition of the chromium salt. Contemporary processes are exclusively based on one-bath procedures and utilize chromium(III). The older two-bath process is now obsolete, mainly because it involved the in situ reduction of chromate, a major environmental and toxicological hazard (cf. chromate toxicity p. 947) to chromium(III) on the hide. A useful review of the history of chromium tannage processes is available.1205... 

Although living organisms contain additional types of fibrous proteins, as well as polysaccharide-based structural motifs, we focused here on the three arrangements that are the most widely distributed. Two of these, the a-keratins and the /3-keratins incorporate polypeptide secondary structures that also commonly occur in globular proteins. Colla-... 

Studies have also pointed out that there is sequence specificity in DP interactions with various IFs (Fontao et al., 2003 Meng et al., 1997 Stappenbeck et al., 1993). Although the details of these studies differ, collectively they highlight the importance of the C PRD plus the last 68 residues for DP s association with keratins and the B PRD plus linker for type III IF interactions. In addition, phosphorylation of serine 2849, which is 23 residues from the DP G-terminus, impairs interactions with IFs and may be involved in regulating the size of the DP pool that is... 

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