Cytochrome b5 type A (CYB5A)

Cytochrome b5 type A (CYB5A) is a human membrane-bound hemoprotein found primarily in the endoplasmic reticulum and outer mitochondrial membrane[1][3][4][5]. Its principal role is serving as an electron carrier for enzymes involved in fatty acid desaturation, steroid biosynthesis, and xenobiotic metabolism, including cytochrome P450s. CYB5A maintains hemoglobin in its reduced, oxygen-binding form and is essential for cellular redox balance. Defects in CYB5A cause hereditary methemoglobinemia, a disorder characterized by impaired oxygen transport in blood, and impact adrenal steroidogenesis. In cancer, CYB5A expression can modulate autophagy and inhibit metastasis by interacting with key signaling pathways[6].

Other names

Cytochrome b5CYB5MCB5Microsomal cytochrome b5 type AMicrosomal cytochrome b5METAGCytochrome b5 type A (microsomal)Epididymis secretory sperm binding proteinType 1 cyt-b5

Metal ions (chromium-containing drugs): interact as substrates with cytochrome b5, affecting redox processes related to oxygenases and detoxification pathways; Indirect regulation: influencing electron flux to enzymes such as cytochrome P450s, affecting metabolic conversion of endogenous compounds and xenobiotics; In cancer: modulation of autophagy through inhibition of the JAK1/STAT3 pathway