Hexone Bases

HEXONE BASES, a name proposed by Kossel (Kossel) for a group of three amino acids (see) that have six carbon atoms and two or several amino or imino nitrogen atoms in their molecules and, because of this, possess alkaline properties. These amino acids are: Lysine (see) and epsilon-diaminocaproic acid: NH2.CH2.(CH2)3.CH(NH2).COOH; Histidine (see) - beta-imidazolyl-alpha-aminopropionic acid: CH2-CH(NH2)-CH2-CH2-CH(NH2)-COOH; Arginine (see) - delta-guanido-alpha-aminovaleric acid: NH2.C(=NH).NH.CH2.(CH2)3.CH(NH2).COOH. All three amino acids occur in the bodies of animals and in plants (especially in germinating seeds) in a free form and participate in the construction of proteins (see). Hexone bases are easily soluble in water, have a sharply alkaline reaction, and, unlike monoamino acids, are precipitated by phosphotungstic acid even from diluted solutions. Proteins containing many hexone bases in their molecules have an alkaline character (globin, histone). Under the influence of microorganisms, hexone bases, losing CO2, transform: lysine into cadaverine NH2.(CH2)5.NH2, histidine into beta-imidazolylethylamine CH2-CH(NH2)-CH2-CH2-CH2-NH2, and arginine into putrescine NH2.(CH2)4.NH2 (see Putrescines). Under the action of the enzyme arginase, arginine decomposes with the formation of urea and ornithine: NH2.(CH2)3.CH(NH2).COOH.