BRS2(KC2) - Amino Acid Substrate Sufficiency

1. Definition

Availability of methionine, serine, glycine, and cysteine supporting methionine cycle and transsulfuration.

2. Constraint Role

Availability of methionine, serine, glycine, and cysteine supporting methionine cycle and transsulfuration. Dietary amino-acid intake supplies substrate and cofactor context for dependent mechanisms in this BRS.

3. Supporting Inputs/Substrates

• Amino acid support ← soy, quinoa
• Cysteine ← eggs, meat, fish
• Glycine ← legumes
• Methionine ← eggs, meat, fish

4. Biological Importance

Availability of methionine, serine, glycine, and cysteine supporting methionine cycle and transsulfuration. Inadequate coverage of these inputs can limit one-carbon flux, remethylation, and downstream methylation-dependent processes across linked FMs and PMs.

5. Connected Mechanisms

• Functional Mechanisms
  • BRS2(FM1) - Methylation Cycle Efficiency
  • BRS2(FM2) - Transsulfuration & Redox Coupling
  • BRS2(FM3) - Methylation–Membrane Coupling
• Primary Mechanisms
  • BRS2(PM3) - SAMe Synthesis
  • BRS2(PM4) - Methionine Cycle Flux
  • BRS2(PM5) - Transsulfuration Pathway
  • BRS2(PM6) - Glutathione Synthesis
  • BRS2(PM7) - Phospholipid Methylation

6. Constraint Stressors / Burdens

• inconsistent methyl-donor intake across days
• low folate, B12, choline, or betaine food patterns where KC1 applies
• inadequate sulfur amino-acid and glycine supply where KC2 applies
• ultra-processed dietary patterns displacing whole-food methyl-donor sources

7. References

1. See linked FM pages for cited evidence.