Cysteine

    Cysteine ​​levels may be elevated due to a CBS SNP that results in upregulation of the enzyme and increased production of cystathionine and cysteine. Zinc is an important cofactor downstream of cysteine ​​in transsulfuration. Because of this, cysteine ​​elevations may also be seen in zinc insufficiency.

    Vitamin B₁₂ may also be a cofactor in peripheral cysteine ​​utilization; therefore, functional deficiencies of vitamin B₁₂ may contribute to higher levels.

    Low dietary protein intake, GI malabsorption, and maldigestion may contribute to lower amino acid levels.

    Because vitamin B₆ is a cofactor at multiple steps within the transsulfuration pathways, deficiency may contribute to decreased cysteine ​​by inhibiting or slowing the enzyme that converts cystathionine to cysteine.

LOW CYSTEINE

•Vitamin B6 cofactor need for the CBS and CTH enzymes

HIGH CYSTEINE

• CBS SNP

• Elevated SAM which directly upregulates CBS enzyme

• High oxidative stress or inflammation

• Zinc cofactor need for GSS enzyme