Food Biochemistry and Food Processing (2 edition)

BLBS102-c07 BLBS102-Simpson March 21, 2012 11:12 Trim: 276mm X 219mm Printer Name: Yet to Come

128 Part 2: Biotechnology and Enzymology

Table 7.1.Names, Symbols (One Letter and Three Letters Code) and Chemical Structures of the 20 Amino Acids

Found in Proteins

Non-polar amino acids

Alanine Ala (A) CH 3 –CH–COOH

NH 2

Valine Val (V)

CH–CH–COOH

NH 2

H 3 C

H 3 C

Leucine Leu (L)

CH–CH 2 –CH–COOH

NH 2

Isoleucine Ile (I)

CH–CH–COOH

NH 2

H 3 CCH 2

H 3 C

Methionine Met (M) CH 3 –S–CH 2 –CH–COOH

NH 2

Tryptophan Trp (W) CH 2 –CH–COOH

NH NH 2

Phenylalanine Phe (P) CH 2 –CH–COOH

NH 2

Proline Pro (P)

COOH

H H

N

+

Polar uncharged amino acids

Glycine Gly (G) H–CH–COOH

NH 2

Asparagine Asp (D) H 2 N–C–CH 2 –CH–COOH

O NH 2

Glutamine Gln (Q) H 2 NC CH 2 CH 2

O

CHCOOH

NH 2

Serine Ser (S) HO CH 2 CHCOOH

NH 2

Threonine Thr (T)

CH 2

CH 3

HO CHCOOH

NH 2

Cysteine Cys (C) HSCH 2 CHCOOH

NH 2

Ty r o s i n e Ty r ( Y ) HO CH 2 CHCOOH

NH 2

Negatively charged amino acids

Glutamate Glu (E) HOOC CH 2 CH 2 CHCOOH

NH 2

Aspartate Asn (N) HOOC CH 2 CHCOOH

NH 2

Positively charged amino acids

Arganine Arg (R) HN CH 2 CH 2 CH 2 CHCOOH

CNH NH 2

NH 2

Lysine Lys (K) H 2 N(CH 2 ) 4 CHCOOH

NH 2

Histidine His (H) CH 2 CHCOOH

HN N: NH^2