Human Biochemistry Volume 1 - Murray R. 1993
Structure and Functions of Proteins and Enzymes
Amino Acids
Structure of Amino Acids
Amino Acids that make up Proteins can be divided into two broad groups based on whether the R-groups attached to the α-carbon atom are polar or nonpolar (Table 3.2).
Table 3.3 lists the three-letter and one-letter Abbreviations for amino acids widely used in biochemistry. One-letter abbreviations are used to represent longer Amino acid sequences (e.g., complete protein sequences).
Amino acids in a free state or incorporated into non-protein compounds play an essential role in numerous metabolic processes (Tables 3.4 and 3.5). For example, the amino acids Ornithine, citrulline, and argininosuccinate (Table 3.4) are involved in urea METABOLISM. Over 20 D-Amino acids have been found in nature. These include D-Alanine and D-glutamate, which are Components of the Cell walls in certain Bacteria, while several other D-Amino acids are found in Antibiotics.
Class="center">Table 3.2. Classification of protein-derived L-α-amino acids based on the relative polarity of their R-groups
|
Nonpolar |
Polar |
|
Alanine |
|
|
Valine |
Asparagine |
|
Isoleucine |
Aspartic acid |
|
Leucine |
|
|
Glutamine |
|
|
Glutamic acid |
|
|
Phenylalanine |
|
Last update: 06/08/2026
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