Action of amino acids on sugars. Formation of melanoidins in a methodical way

Abstract

cf. C. A., 6, 621. When glycocoll is warmed with 4 Pts. glucose in 3-4 pts. H2O, the liquid slowly assumes a characteristic yellow color, changing to a dark brown and followed by foaming (CO2). Special expts. show that the O of the CO2 is not furnished by the air, and analysis of the residue indicates that 12 mols. of H2O are lost to each mol. CO2. The CO2 therefore comes from the CO2H group of the glycocoll. Assuming that this loss of CO2 is accompanied by a union of the N with aldehyde C of the sugar, the glucose mols. (at least 2 in no.) forming part of the new compds. must suffer dehydrations resulting in the appearance of double bonds or, possibly, rings. Various other amino acids act in the same way on glucose, and similarly various sugars act in this way on glycocoll;xylose and arabinose immediately, fructose, galactose, glucose and mannose quite rapidly, lactose and maltose slowly, saccharose not at all for several hrs. and then very slowly. These substances bear the same relation to melanoidins obtained by the hydrolysis of proteins and tissues that synthetic polypeptides bear to natural peptones. [on SciFinder(R)]