Influence of β-Carboline Produced from Glucose and Tryptophan on Protein Synthesis of Chicken Embryo Myoblasts

Abstract

Glycation is non-enzymatic reaction causing dehydrating condensation between carbonyl group of reducing sugars and amino group of proteins. In the case of glucose and tryptophan, this reaction forms Schiff base followed by two different reactions of Amadori rearrangement generating Amadori product and Pictet-Spengler reaction generating (1R,3S)-1-(D-gluco-1,2,3,4,5-pentahydroxypentyl)-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (PHP-THβC). Amadori product undergoes further complex reaction to form advanced glycation end products (AGEs). PHP-THβC is one of β-carbolines consisting of an indole skeleton and various side chains. As chickens are known to be one of hyperglycemic animals, it seems to be accelerated glycation and easily produced PHP-THβC when chickens are given excess dietary tryptophan. However, there are little investigations of physiological role of glycated tryptophan. In this study, therefore, various concentrations of PHP-THβC added into culture medium for chicken embryo myoblasts and protein synthesis was measured to clarify the relation of PHP-THβC to muscle protein synthesis. Protein synthesis of chicken embryo myoblasts was decreased by addition of PHP-THβC in range of physiological concentrations in the culture medium. In conclusion, it was supposed that the elevation of PHP-THβC levels in the serum of hyperglycemic animals would decrease muscle protein synthesis.