# Pyruvate Processing --- **Pyruvate processing**, or **pyrurvate oxidation** is a linking step in [[cellular respiration]] that follows [[glycolysis]] and proceeds the [[citric acid cycle]]. During this step, pyruvate is combined with [[coenzyme a]] and turned into [[acetyl CoA]]. [[Pyruvate]] is formed in the [[cytoplasm|cytosol]], and then crosses into the [[mitochondria|mitochondrial matrix]] where it can be turned into acetyl CoA. Once it enters the mitochondria, it cannot leave again. Pyruvate processing starts with a 3-carbon pyruvate molecule. One carbon (and two oxygen) is released as CO$_2$, and the released free energy is used to reduce one [[NAD|NAD+]] to [[NAD|NADH]]. [[Coenzyme A]] comes along and is attached to the remaining two carbons that are left of the pyruvate and form [[acetyl CoA]]. ![[pyruvate processing.png]] Pyruvate processing is irreversable; [[acetyl CoA]] cannot be reconverted back into pyruvate. ![[pyruvate and acetyl CoA.png]] ___