Pyruvate dehydrogenase is an enzyme that catalyzes the reaction of pyruvate and a lipoamide to give the acetylated dihydrolipoamide and carbon dioxide. The conversion requires the coenzyme thiamine pyrophosphate. ... Collectively E1-E3 transform pyruvate, NAD+, coenzyme A into acetyl-CoA, CO2, and NADH.
No, it's because we need to breathe. Your body needs oxygen. Air pressure has little to nothing to do with it as far as I know.
