Predicted to enable FAD binding activity. Predicted to be located in mitochondrion. Human ortholog(s) of this gene implicated in estrogen-receptor negative breast cancer and methemoglobinemia. Is an ortholog of human CYB5R1 (cytochrome
b5 reductase 1); CYB5R2 (cytochrome
b5 reductase 2); and CYB5R3 (cytochrome
b5 reductase 3).