Keratin biosynthesis

Barrier disruption is observed in variously induced scaly skin4 and is known to cause changes in epidermal biochemical processes, including lipid biosynthesis,5 DNA synthesis,6 calcium localization,7 and cytokine production.8 Up-regulation of specific keratin molecules and adhesion... 

The fiber surface is bounded by a thin membrane 100 A thick called the epicuticle. The cuticle is a scaly, tubular layer and consists of flattened cells which overlap to give a rachet-like profile to the fiber. Each scale cell contains two distinct layers, a keratinous outer layer termed the exocuticle and a nonkeratinous inner layer that appears to be derived from cytoplasmic debris and is termed the endocuticle. There is some evidence that the exocuticle itself is complex with an outer cystine-rich layer termed exocuticle a. In coarse fibers the cuticle may be many scale-cells thick and where the cells overlap they are separated by an intercellular layer formed during biosynthesis by the deposition of nonkeratinous protein between the cell membranes. This layer is sometimes referred to as intercellular cement. 

Vitamin A performs numenius biochemical functions. It promotes the production nf mucus by the basal cells of the epithelium, whereas in its absence keratin can be fonned. Vitamin A performs a function in the biosynthesis of glycogen and some steroids, and increased quantities nf coen/yme Q are found in the livers nf vitamin-deficicnt rats. Significantly. the best-known action of vitamin A is its function in the chemistry of vision. 

Fraser, R. et al. In Keratins, Their Composition, Structure and Biosynthesis, Chapters 2 and 3. Thomas, Springfield, IF (1972). 

R.D.B. Fraser, T.P. MacRae, and G.E. Rogers, Keratins, Their Composition Structure and Biosynthesis, Charles C. Thomas, Springfield, Illinois, 1972. 

Fraser RDB, MacRae TP, Rogers GE. Keratins Their Composition, Structure, and Biosynthesis. Springfield, IL Charles C Thomas, 1972. 

To the biochemist, the epiderm cell in mammals is characterized particularly by the biosynthesis of keratin, a protein rich in S-S linkages. This type of cell is also one of the sites of synthesis of cholesterol. The cells of the sebaceous glands are notable in bringing about the rapid transformation of the whole of their content into a mixture of many lipides, saturated alcohols, and hydrocarbons, etc. 

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