Defective Transcellular Transport of Amino Acids

Abstract

Transcellular transport mechanisms are responsible for the transport of free amino acids through epithelial cells and are mainly present in cells of the intestinal mucosa and the renal tubules. Most amino acids are transported via a sodium-dependent transport system. However, sodium-independent transport and passive diffusion exist. Transmembrane transporters may be specific for single amino acids (e.g. histidine, glycine) or for groups of amino acids (e.g. dibasic amino acids, dibasic amino acids and cystine, neutral amino acids or dicarboxylic amino acids).