Predicted to enable heme binding activity. Located in perinuclear region of cytoplasm. Used to study hematopoietic system disease. Human ortholog(s) of this gene implicated in methemoglobinemia; methemoglobinemia and ambiguous genitalia; and stomatitis. Is an ortholog of human CYB5A (cytochrome
b5 type A) and CYB5B (cytochrome
b5 type B).