n. 白氨酸

[化] 亮氨酸; 白氨酸; 异己氨酸

[医] 亮氨酸, 白氨酸

[ noun ]
a white crystalline amino acid occurring in proteins that is essential for nutrition; obtained by the hydrolysis of most dietary proteins
<noun.substance>

Leucine \Leu"cine\ (l[=oo]"s[=e]n), Leucin
\Leu"cin\(l[=u]"s[i^]n), n. [Gr. leyko`s white.] (Physiol.
Chem.)
a naturally occurring alpha-amino acid
({(CH3)2CH.CH2.CH(NH2)-COOH}), one of the building units of
almost all proteins of living organisms, both animal and
vegetable. It is one of the essential amino acids (not
synthesized by the human body, a required component for
proper nutrition), and is hydrophobic in character when bound
in proteins. In isolated form it is a white, crystalline,
zwitterionic substance formed, e. g. by the decomposition of
proteins by pancreatic digestion, by the action of boiling
dilute mineral acid, or by putrefaction. Chemically it is to
be considered as amido-caproic acid. It occurs as two optical
isomers, the L- and D-forms. The L-form, L-leucine, is the
natural form, present in most proteins.
[1913 Webster +PJC]