ROLE OF NON-PROTEIN AMINO ACIDS IN AUTOIMMUNE DISEASES

Abstract

Many nonprotein amino acids (NPAAs) are plant secondary metabolites and have a similar chemical structure , size, shape and charge to protein amino acids and can be mistakenly used in protein synthesis, interfere in biochemical pathways, overstimulate receptors or chelate metal ions. The Consumption of a number of plants that contain NPAAs has been shown to have acutely toxic effects in humans. The consumption of some seeds or vegetables that contain NPAAs inuences some people as a trigger for some diseases or as an exacerbating factor. The effects of NPAAs on human health are not well understood. It has been observed that chimpanzees fed alfalfa and also a volunteer subject who have intake alfalfa tablets have both developed a disease with all the characteristics of lupus erythematosus ( an autoimmune disease) and by suppressing the consumption of alfalfa the disease disappears. Most of NPAAs are of plant origin; these do not form part of the primary structure of proteins, they act as antimetabolites and most are found in higher plants; they have the same basic structure as amino acids of animal origin. The substitution of a protein amino acid in protein synthesis produces abnormal proteins which generate antibodies and modication of autoantigens as mechanism to break immunological tolerance and trigger autoimmunity. Auto-antibodies formation is a characteristic of autoimmune disease. The toxic potential of NPAAs depend the amount ingested and the consumption time. Chronic exposure to NPAAs could contribute to autoimmune disease development in genetically susceptible individuals