Pyruvate decarboxylase is found as part of the pyruvate dehydrogenase complex in higher organisms where it is referred to as E1. 24 copies of it are found in the Azotobacter complex along with two other enyzmatic activities, referred to as E2 and E3.

Pyruvate decarboxylase is also part of the pathway involved in alcoholic fermentation in yeast. In the reaction, pyruvate is converted to acetaldehyde, which is subsequently converted to ethanol by action of the enzyme alcohol dehydrogenase:

Pyruvate <=> Acetaldehyde + CO2

Pyruvate decarboxylase uses thiamine pyrophosphate as a coenzyme.