Abstract
The study describes the vertical distribution of free amino acids in the porcine epidermis as compared to the human integument, using a micro-determination TLC method based on the reaction of amino acids with dansyl chloride. This microanalytical approach demonstrated 22 free amino acids, with the relatively largest amounts being present for acidic amino acids and their amides. It was obvious that the relative amounts of certain amino acids (alanine, proline, valine, glutamine, histidine, glycine, threonine) decreased, whereas acidic amino acids (glutamic acid, aspartic acid) increased from the stratum basale up to the stratum corneum. This distributional pattern could be verified for the dorsal and lateral body regions of the pig breeds used, and for man. The results obtained are discussed in view of the development of epidermal keratinization.