Table of Amino Acid Properties

Name & Structure Polarity Charge Hydrophilic/ 3 ionisable groups Typical Notes
abbreviations hydrophobic group pKa
Alanine, Ala, A Non-polar Neutral Hydrophobic No Terminal
alpha
carboxyl
group pKa
is 3.1
Arginine, Arg, R Polar Positive Hydrophilic Yes 12.5




Asparagine, Polar Neutral Hydrophilic Yes
Asn, N


Aspartic acid, Polar Negative Hydrophilic Yes 3.9
Asp, D


Cysteine, Cys, C Polar Neutral Hydrophilic Yes 8.3 Contains a free thiol (SH) group so can
form covalent di-sulfide bonds. It is a
good ligand.
Glutamine, Gln, Polar Neutral Hydrophilic Yes
Q



Glutamic acid, Polar Negative Hydrophilic Yes 4.3
Glu, E (average
with asp =
4.1)