Cytochrome b subunit of cytochrome bc1 complex (None)

The cytochrome b subunit is a transmembrane protein containing two noncovalently bound heme groups (heme bL and bH) and is a principal component of the cytochrome bc1 complex (mitochondrial Complex III)[5][8]. This complex facilitates electron transfer from ubiquinol to cytochrome c, coupling this process to proton translocation and the creation of a proton gradient necessary for ATP synthesis[3][5][8]. Cytochrome bc1 is structurally conserved across species, with the cytochrome b subunit forming the core of the enzymatic activity. Its mechanism involves the Q-cycle, coordinating conformational changes and redox reactions within the complex. Mutations in cytochrome b significantly impact respiratory efficiency and are linked to a range of pathologies, including inherited mitochondrial disorders and aging-related diseases[3]. The cytochrome bc1 complex, particularly the cytochrome b subunit, is targeted by several clinically relevant and agricultural drugs, especially in the context of infections and parasitic diseases[6][2].

Other names

Cyt b (especially in context with bc1 complex)Cytochrome bMitochondrial Complex III subunit b

Inhibition of electron transfer (blockage of Q-cycle at specific quinone binding sites by drugs); Disruption of proton gradient, leading to cessation of ATP synthesis; Induction of electron leakage and increased reactive oxygen species if defective