Stratum corneum free amino acid

Free Amino Acid Content in Stratum Corneum. 99... 

Koyama, J., Horii, I., Kawasaki, K., Nakayama, Y., Morikawa, Y., and Mitsui, T. Free amino acids of stratum corneum as a biochemical marker to evaluate dry skin. J. Soc. Cosmet. Chem. 35 183-195 (1984). 

Denda, M., Hori, J., Koyama, J., Yoshida, S., Namba, R., Takahashi, M., Horii, I., and Yamamoto, A., Stratum corneum sphingolipids and free amino acids inexperimentally-induced scaly skin. Arch. 

Scott, I.R., Harding, C.R., and Barrett, J.G. Histidine-rich protein of keratohyalin granules source of the free amino acids, urocaninc acid and pyrrolidone carboxylic acid in the stratum corneum. Biochim. Biophys. Acta. 719 110-117 (1982). 

Katagiri, C., Sato, J., Nomura, J., and Denda, M. (2003) Changes in environmental humidity affect the water-holding property of the stratum corneum and its free amino acid content, and the expression of filaggrin in the epidermis of hairless mice. J. Dermatol. Sci. 31 29-35. 

Takahashi, M. and Tezuka, T., The content of free amino acids in the stratum corneum is increased in senile Xerosis, Arch. Dermatol. Res., 295, 448 -52, 2004. 

Although the hypothesis that the large molecule of soluble native collagen, 1.5 x 300 nm in length, could penetrate the skin is generally refuted today, the discussion about the potential penetration of smaller peptides is still open. Absorption and accumulation of free amino acids is well documented to occur in the stratum corneum (77,78), yet this does not necessarily mean that larger polymers of these small molecules could penetrate. 

The fate of radiation incident upon the skin is determined by the optical properties of the tissue. Two basic interactions with photons occur - scattering and absorption. When radiation strikes the skin, part is scattered back to the environment, part is absorbed in various layers, and part is transmitted inward until the energy has been dissipated. At the surface of the stratum corneum a fraction of about 5-7% of the incident radiation is scattered backward (reflected), since the refractive index of the stratum corneum (nsc l-55) is much higher than that of air (n = 1.00). In the epidermis, aromatic amino acids (both free and in protein, wavelength of absorption maximum Xmax near 275 nm), urocanoic acid (X av near 277 nm at pH 7.4), nucleic acids (X ax near 260 nm), and melanin (broad absorption... 

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