Aerobic oxidation of reduced cytochromes shows P/O ratio of

ADP:O or P:O Ratio: The NAD-dependant dehydrogenases such as malate, pyruvate, a-ketoglutarate, isocitrate, etc. produce three high energy phosphate bonds for each pair of electrons transferred to O2 because they have P: O ratio of 3. Thus P: O ratio is a measure of how many moles of ATP are formed from ADP by phosphorylation per gram atom of oxygen used. This is measured as the number of moles of ADP (or Pi) that disappear per gram atom of oxygen used. Phosphate group esterified P:O ratio = ___________________________________ Electron pairs transferred P:O ratio x 7.3 Efficiency = ______________________ x 100 51 K.Cal However, P:O ratio in case of FADH2 is 2 and therefore efficiency is lower in that case.Ref: MN Chatterjea Textbook of Medical Biochemistry, 7th Edition, Page no: 142