Amino Acids Working Group Meeting Book (July 3, 2018)

Background • Although cysteine is listed in the table, as it fits the general structure for D -amino acids, its disulfide form, cystine, is obviously included in the working definition of amino acids. The two are equivalent from a nutrit- ion point of view and regulations treat them as such. • Because of method overlap, taurine (2-amino-ethanesulfonic acid) is also included in this analyte category, despite not fitting the basic definition.

pK 2

pK 1

pK 3

Amino Acid

Abbrev.

Short

Mass (Da)

pI

(α- + NH 3

)

(α-COOH)

Alanine Arginine

Ala Arg Asn Asp Cys Glu Gln Gly Pro Ser Leu Lys Met Phe Thr Trp Val Tau Tyr His Ile

A R N D

89.09 174.2 132.1 133.1 121.2 147.1 146.1 75.07 115.1 105.1 181.2 155.2 131.2 131.2 146.2 149.2 165.2 119.1 204.2 117.1 125.2

2.35 1.82 2.14 1.99 1.92 2.19 2.17 2.35 1.95 2.19 2.20 1.82 2.32 2.33 2.16 2.13 1.83 2.09 2.46 2.39 1.50

9.87 8.99 8.72 9.82 10.7 9.47 9.13 9.78 9.21 9.21 9.33 9.76 9.74 9.06 9.28 9.31 9.41 9.74 8.74 9.1

-

6.01

12.48

10.76

Asparagine Aspartic acid

-

5.41 2.85 5.05 3.15 5.65 6.06 6.30 5.68 5.64 7.58 6.05 6.01 9.60 5.74 5.49 5.60 5.89 5.97 5.12

3.86 8.18 4.07

Cysteine

C E

Glutamic acid

Glutamine Glycine Proline Serine Tyrosine Histidine Isoleucine

Q G P S Y H

- - - -

10.64

10.46

6.04

I

- -

Leucine

L

Lysine

K

10.54

Methionine

M

- - -

Phenylalanine

F T

Threonine Tryptophan

W

5.89

Valine

V

- -

Taurine

-