Webster's 1828 Dictionary
LEUCIN, LEUCINE
n.[Gr. white. ] A peculiar white pulverulent substance obtained from beef-fibers, treated with sulphuric acid, and afterwards with alcohol.
Webster's 1913 Dictionary
LEUCIN
Leu "cin, n. Etym: [Gr. (Physiol. Chem. )
Defn: A white, crystalline, nitrogenous substance formed in the decomposition of albuminous matter by pancreatic digestion, by the action of boiling dilute sulphuric acid, and by putrefaction. It is also found as a constituent of various tissues and organs, as the spleen, pancreas, etc. , and likewise in the vegetable kingdom. Chemically it is to be considered as amido-caproic acid. (CH3 )2CH.CH2.CH (NH2 )-COOH. L-leucine, the natural form, is present in most proteins.
New American Oxford Dictionary
leucine
leu cine |ˈlo͞oˌsēn, -sin ˈlusən | ▶noun Biochemistry a hydrophobic amino acid that is a constituent of most proteins. It is an essential nutrient in the diet of vertebrates. [Chem. formula: (CH 3 ) 2 CHCH 2 CH (NH 2 )COOH. ] ORIGIN early 19th cent.: coined in French from Greek leukos ‘white ’ + -ine 4 .
Oxford Dictionary
leucine
leucine |ˈluːsiːn | ▶noun [ mass noun ] Biochemistry a hydrophobic amino acid which is a constituent of most proteins. It is an essential nutrient in the diet of vertebrates. ●Chem. formula: (CH 3 ) 2 CHCH 2 CH (NH 2 )COOH. ORIGIN early 19th cent.: coined in French from Greek leukos ‘white ’ + -ine 4 .
The Wordsmith Dictionary