leucin (lu's in)

Amido-iso-caproic acid, (CH3)2CH.CH2.CHNH2.COOH. A white substance, crystallizing in shining plates, soluble in about fifty parts of water. It has both acid properties (car boxy group) and basic properties (amido group). It is found widely distributed in plant and animal life. All the proteins which have been closely studied yield 1. upon hydrolytic cleavage and most proteins yield an abundance of this acid. It has been isolated as a normal constituent of the pancreas, the spleen, and many other glands, its presence being probably due to the action of the enzymes present in the gland upon the proteins of that gland. In pathological conditions it is found in the urine. L. contains one symmetrical carbon atom. The levo form is the one found in nature. Upon feeding the racemic form, the unnatural component, the dextro form, is excreted in the urine; LEUKOCYTOGENESIS the other form is retained or used up in the organism. [Gr., leukos, white.]