Amino acids have two configurations, namely L-type and D-type isomers. The 20 common basic amino acids are basically L-type amino acids (except glycine). These amino acids make up most of the proteins in living organisms and play an important role in a series of biochemical systems. The following are 20 common amino acid types and their properties.
| Amino Acid Name | Abbreviation | pKa1 | pKb2 | ||
| Alanine | Ala/A | 2.35 | 9.87 | Add To Cart | Inquiry |
| Arginine | Arg/R | 1.82 | 8.99 | Add To Cart | Inquiry |
| Asparagine | Asn/N | 2.14 | 8.72 | Add To Cart | Inquiry |
| Aspartic acid | Asp/D | 1.99 | 9.9 | Add To Cart | Inquiry |
| Cysteine | Cys/C | 1.92 | 10.7 | Add To Cart | Inquiry |
| Glutamic acid | Glu/E | 2.1 | 9.47 | Add To Cart | Inquiry |
| Glutamine | Gln/Q | 2.17 | 9.13 | Add To Cart | Inquiry |
| Glycine | Gly/G | 2.35 | 9.78 | Add To Cart | Inquiry |
| Histidine | His/H | 1.8 | 9.33 | Add To Cart | Inquiry |
| Isoleucine | Ile/I | 2.32 | 9.76 | Add To Cart | Inquiry |
| Leucine | Leu/L | 2.33 | 9.74 | Add To Cart | Inquiry |
| Lysine | Lys/K | 2.16 | 9.06 | Add To Cart | Inquiry |
| Methionine | Met/M | 2.13 | 9.28 | Add To Cart | Inquiry |
| Phenylalanine | Phe/F | 2.2 | 9.31 | Add To Cart | Inquiry |
| Proline | Pro/P | 1.95 | 10.64 | Add To Cart | Inquiry |
| Serine | Ser/S | 2.19 | 9.21 | Add To Cart | Inquiry |
| Threonine | Thr/T | 2.09 | 9.1 | Add To Cart | Inquiry |
| Tryptophan | Trp/W | 2.46 | 9.41 | Add To Cart | Inquiry |
| Tyrosine | Tyr/Y | 2.2 | 9.21 | Add To Cart | Inquiry |
| Valine | Val/V | 2.39 | 9.74 | Add To Cart | Inquiry |
Amino Acids by Side Chain
The amino acids encoded by the 20 DNA bases can be divided into 4 categories according to the chemical properties of their side chains:
Hydrophobic amino acids, including 8 types: Alanine, Valine, Leucine, Isoleucine, Proline, Phenylalanine, Tryptophan, Methionine;
Neutral amino acids, including 7 types: Glycine, Serine, Threonine, Cysteine, Tyrosine, Asparagine, Glutamine;
Basic amino acids, including 3 types: Lysine, Histidine, Arginine;
Acidic amino acids, including 2 types: Aspartic acid, Glutamic acid.
The side chains of hydrophobic amino acids are non-polar, and most of them are hydrocarbon or aromatic groups; the side chains of basic amino acids contain basic amine groups, so they easily attract hydrogen ions in aqueous solution and carry positive charges; the side chains of acidic amino acids contain acidic carboxyl groups, so they easily give up hydrogen ions in aqueous solution and carry negative charges. Neutral, basic and acidic amino acids are collectively called hydrophilic amino acids, or polar amino acids.
Amino Acid Structure
The following are the chemical structures of 20 amino acids
