Pyruvate dehydrogenase（PDH）催化pyruvate轉化為acetyl-CoA的過程中會依序釋放出：
acetyl-CoA, \mathrm{CO}_{2}, NADH
\mathrm{CO}_{2}
acetyl-CoA, \mathrm{CO}_{2}, \mathrm{FADH}_{2}
\mathrm{FADH}_{2}
\mathrm{CO}_{2}, \mathrm{FADH}_{2}, acetyl-CoA
\mathrm{CO}_{2}, acetyl-CoA, NADH
