nounIntermediate
Definition
The smallest and simplest amino acid (R group = H), giving it unique conformational flexibility.

Detailed Explanation

The smallest and simplest amino acid (R group = H), giving it unique conformational flexibility. Glycine makes up every third residue in collagen's Gly-X-Y repeat — its small size allows it to fit in the crowded interior of collagen's triple helix. Beyond structural roles, glycine is an inhibitory neurotransmitter in the spinal cord and brainstem, a precursor for glutathione and heme synthesis, and a conjugation agent for drug metabolism. Dietary glycine may be conditionally essential — the body synthesizes ~3 g/day but may need 10+ g/day for optimal collagen and glutathione production.

Key Facts

  • The smallest and simplest amino acid (R group = H), giving it unique conformational flexibility.
  • Glycine makes up every third residue in collagen's Gly-X-Y repeat — its small size allows it to fit in the crowded interior of collagen's triple helix.
  • Beyond structural roles, glycine is an inhibitory neurotransmitter in the spinal cord and brainstem, a precursor for glutathione and heme synthesis, and a conjugation agent for drug metabolism.
  • Dietary glycine may be conditionally essential — the body synthesizes ~3 g/day but may need 10+ g/day for optimal collagen and glutathione production.
Related Terms Proline Hydroxyproline Collagen Amino Acid Glutathione

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