2I961528109672ENSG00000166347ENSMUSG00000024646P00167P56395NM_001190807NM_001914NM_148923NM_025797NM_001348159NP_001177736NP_001905NP_683725NP_080073NP_001335088Cytochrome b5, form A (gene name CYB5A), is a human microsomal cytochrome b5.

[5] Cytochrome b5 is a membrane bound hemoprotein which functions as an electron carrier for several membrane bound oxygenases.

It has two isoforms produced by alternative splicing.

Isoform 1 is bound to the cytoplasmic side of the endoplasmic reticulum.

Defects in CYB5A are the cause of type IV hereditary methemoglobinemia.