Figure 1.

Proposed mechanism of coenzyme Q₁₀ and carnitine effect in sperm mitochondria. Acyl-CoA: acyl-coenzyme A; CPT I: carnitine phosphate transpeptidase I; CPT II: carnitine phosphate transpeptidase II; CoQ: coenzyme Q; VDAC: voltage dependent anion channel; ATP: adenosine triphosphate; ADP: adenosine diphosphate; Pi: inorganic phosphate; I, II, III, IV, and V: respiratory chain complexes; H⁺ proton; e⁻: electron; Q-cycle: coenzyme Q cycle; cyt c: cytochrome c; NADH: reduced nicotinamide adenine dinucleotide; NAD⁺: nicotinamide adenine dinucleotide; FADH₂: reduced flavin adenine dinucleotide; FAD: flavin adenine dinucleotide; O₂ ^∙−: superoxide radical; H₂O₂: hydrogen peroxide; OH^∙: hydroxyl radical; H₂O: water; O₂: oxygen.