Amino Acids Structure and Properties

Amino Acids and Peptides

• Ornithine is a biologically important amino acid that does not enter the protein structure.
• Polypeptides contain more than 10 amino acids.
• The isoelectric point (pI) of an amino acid is the pH at which the amino acid has no net charge.
• Enkephalin is an example of a biologically active peptide.
• Glycine is the only optically inactive amino acid.
• The amino group (-NH2) and the carboxyl group (-COOH) are directly attached to the α carbon in each amino acid.
• Amino acids can be classified into three categories based on the number of carboxylic and amino groups: monoamino monocarboxylic acids, monoamino dicarboxylic acids, and diamino monocarboxylic acids.
• Aromatic amino acids contain rings in their side chains.
• Amino acids can be classified into two categories based on their nutritional needs: essential amino acids and non-essential amino acids.
• Methionine is a neutral amino acid that contains a sulfur atom in its side chain.
• Arginine and histidine are amino acids that must be taken with diet in growing infants and children.
• Peptides contain less than 50 amino acids linked by peptide bonds.
• Pantothenic acid is a part of coenzyme A.
• Beta-endorphin is a biologically active peptide with analgesic effect more powerful than morphine.
• Amino acids can be classified into acidic, basic, and neutral amino acids based on the pH of their side chains.
• Aromatic amino acids contain rings in their side chains.
• Aspartic acid and glutamic acid are classified as acidic and contain two carboxylic groups.
• All amino acids are optically active, except for glycine.
• Amino acids can be classified into two categories based on their nutritional needs: essential amino acids and non-essential amino acids.
• The amino group (-NH2) and the carboxyl group (-COOH) are directly attached to the α carbon in each amino acid.