393
/
_ _ _ _ _ _ _ _ _ _ _ 1
CHa
Threonine
CH3CHOH .CH NHzCOOH
SCH,
I
Methionine
OHz*CHz*CH NH2COOH
-CH,CH NHz COOH
0
Phenylalanlne
Acyclical derivatives
of Q -amino-butyric
-
the next higher
homologue of alanine
CH 2 CH NH 2 COOH
OJ
Tryptophan
NH
I
I
1
I
I
I
I Cycllcal derivatives
I
-
I
I
I
I
I
I
I
of alanlne
' Hexone' bases: all
t
NH
\\
/
NH2
Arglnlne C -NH(CH,)*CH NHzCOOH
'
I
I
I
lsoteucine
CH .CH NHzCOOH
I/
I
are basic amlnoacids and all contain SIX carbon
atoms
The only branchedchain aliphatic
a mino-ac ids known
to occur in nature.