The link reaction
In the link reaction, pyruvate enters the matrix of a mitochondrion and is:
• decarboxylated: CO2 is removed from the pyruvate and then diffuses out of
the mitochondrion and out of the cell.
• dehydrogenated: Hydrogen is removed from the pyruvate, and is picked up
by NAD, producing reduced NAD. This converts pyruvate into a 2-
carbon compound.
• combined with coenzyme A to give acetylcoenzyme A (ACoA).
Coenzyme A consists of:
• adenine
• ribose (making a nucleoside together with adenine)
• pantothenic acid (a B vitamin).
Coenzyme A transfers an acetyl group (with 2 carbon atoms) from pyruvate into
the Krebs cycle and plays a central role in respiration. It is present in small
quantities in a cell and is recycled.
