Antioxidant enzymes

rs4880 (SOD2, Ala16Val): mitochondrial manganese superoxide dismutase converts superoxide into H₂O₂. The variant sits in the mitochondrial targeting sequence; the Ala allele is imported efficiently and yields about 40 percent more active enzyme there, while the Val allele is partly arrested in the inner membrane and degraded (Sutton 2005). rs1050450 (GPX1, Pro198Leu): glutathione peroxidase 1 further breaks down H₂O₂; the Leu allele goes along with lower enzyme activity (Arsova-Sarafinovska 2008). rs1001179 (CAT, catalase): a direct H₂O₂ detoxifier; the effect allele lowers expression. rs1800566 (NQO1, Pro187Ser): protects against quinone toxicity; the T allele contributes substantially to population variation in enzyme activity, and homozygous carriers have very low residual activity (Lajin 2013).

These four enzymes form the built-in panel 'Antioxidant Enzymes' and together describe how well a cell buffers radicals. An unfavourable profile is not a disease finding but a pointer to higher oxidative stress pressure; it can explain why someone reacts more sensitively to loads such as smoking, intense exercise or environmental toxins. Blanket antioxidant supplementation cannot be derived from it.

The functional effects of the individual variants are documented; their disease associations are inconsistent by population and should not be over-interpreted. Genome shows the markers as technical evidence.