Amino Acid Structure and Classification

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@MindBlowingElder794

Study Notes

There are roughly 300 amino acids found in nature, but only 20 of them are present in proteins.
Every amino acid has four groups attached to its alpha (α) carbon:
- Amino group (NH2)
- Carboxyl group (COOH)
- Hydrogen atom (H)
- Side chain or radical group (R)

All amino acids are α-amino acids, meaning the amino group is attached to the second carbon (next to the carboxyl group).
Amino acids are L-Amino acids, meaning the α-amino group is in the left-side configuration.

Acidic: Contain more than one -COOH group (e.g., Aspartate and Glutamate).
Basic: Contain more than one -NH2 group (e.g., Ornithine, Lysine, Arginine, and Histidine).
Neutral: Contain one COOH and one -NH2 group (e.g., Glycine, Alanine).
Branched: Valine, Leucine, and Isoleucine.
Non-Branched: All other amino acids.
Aromatic: Contain phenyl or phenol rings (Phenylalanine, Tyrosine).
Heterocyclic: Contain other types of rings (Tryptophan, Histidine, Proline, and Hydroxyproline).
Aliphatic: Do not contain any rings.

Essential: Essential amino acids are not synthesized in the body and must be obtained through diet. Their deficiency can affect growth and health.
- Threonine
- Valine
- Leucine
- Isoleucine
- Lysine
- Methionine
- Phenylalanine
- Tryptophan
Semi-Essential: Not required for adults but are essential for children. Synthesized in the body, but not enough for children.
- Histidine
- Arginine
Non-Essential: Can be synthesized in the body.
- All other amino acids.

Ketogenic: Metabolized to ketone bodies (e.g., Leucine and Lysine).
Mixed (Ketogenic and Glucogenic): Metabolized to both glucose and ketone bodies (e.g., Threonine, Isoleucine, Phenylalanine, Tyrosine, and Tryptophan).
Glucogenic: Metabolized to glucose (e.g., All other amino acids).

Structural:
- Part of body peptides and proteins (e.g., plasma proteins, tissue proteins, enzymes).
- Found in hormones (e.g., Thyroxine and catecholamines)
- Present in amines (e.g., Histamine: a vasodilator).
Neurotransmitters: (e.g., Glycine, Glutamate).
Detoxication: (e.g., Glycine).
Health and Growth: Important for infants and adults.