L-leucine is an essential amino acid with the chemical formula of C6H13NO2. It is an enantiomer with D-leucine. It is a white glossy hexahedral crystal or a white crystalline powder at room temperature. Odorless, slightly bitter. Sublimate at 145-148 ℃. Melting point 293~295 ℃ (decomposition). In the presence of hydrocarbons, it is stable in inorganic acid aqueous solution. Slightly soluble in ethanol (0.07%), soluble in dilute hydrochloric acid, alkaline hydroxide and carbonate solution. Insoluble in ether.
Brief History of Research
L-leucine was first isolated from cheese by Proust in 1819. Later, Bracannot obtained its crystal from the acid hydrolysate of muscle and wool and named it leucine. L-leucine is one of the eight essential amino acids for human body. It belongs to the fatty amino acid group of twenty protein amino acids. It is called three branched chain amino acids together with L-isoleucine and L-valine.