oic acid.

CH_{3}
\
Isoleucine, C_{6}H_{13}NO_{2}, CH.CHNH_{2}.COOH,
/
C_{2}H_{5}
amino-methylethyl-propionic acid.

/ \
Phenylalanine, C_{9}H_{11}NO_{2}, | |CH_{2}.CHNH_{2}.COOH,
| | phenyl-amino-propionic acid.
\ /

/ \
Tyrosine, C_{9}H_{11}NO_{3}, | |CH_{2}.CHNH_{2}.COOH,
OH| | paraoxy-phenylalanine.
\ /

Cystine, C_{6}H_{12}N_{2}O_{4}S_{2}, HOOC.CHNH_{2}.CH_{2}S-SH_{2}C.
CHNH_{2}.COOH, di(thio-amino-propionic acid).

B. Monoamino-dicarboxylic acids:

Aspartic acid, C_{4}H_{7}NO_{4}, HOOC.CH_{2}.CHNH_{2}.COOH,
amino-succinic acid.

Glutamic acid, C_{5}H_{9}NO_{4}, HOOC.CH_{2}.CH_{2}.CHNH_{2}.COOH,
amino-glutaric acid.

C. Diamino-monocarboxylic acids:

Ornithine, C_{5}H_{12}N_{2}O_{2},
H_{2}N.CH_{2}.CH_{2}.CH_{2}.CHNH_{2}.COOH, di-amino-valerianic acid.

Lysine, C_{6}H_{14}N_{2}O_{2},
H_{2}N.CH_{2}.CH_{2}.CH_{2}.CH_{2}.CHNH_{2}.COOH,
di-amino-caproic acid.

Arginine, C_{6}H_{14}N_{4}O_{2},

NH_{2}
/
HN=C
\
NH.CH_{2}.CH_{2}.CH_{2}.CHNH_{2}.COOH,

guanidine-amino-valerianic acid.

Di-amino-oxysebacic acid, C_{11}H_{12}N_{2}O_{3}.

Di-amino-trioxydodecanic acid, C_{12}H_{26}N_{2}O_{3}.

D. Monoimido-monocarboxylic acids:

Proline, C_{5}H_{9}NO_{2}, H_{2}C---CH_{2}
| |
H_{2}C CH.COOH, pyrrolidine-carboxylic
\ / acid
N
|
H

Oxyproline, C_{5}H_{9}NO_{3}, proline with one (OH) group.

E. Monoimido-monoamino-monocarboxylic acids.

Histidine, C_{6}H_{9}N_{3}O_{2}, HC===C--CH_{2}.CHNH_{2}.COOH,
| | imidazole-amino-propionic
N NH acid.
\\/