List four possible metabolic fates for pyruvate in a mammalian cell. Indicate the type of reaction that occurs. What additional reaction occurs in yeast?

• The pyruvate molecule plays a crucial role in metabolic pathways.
• It has a variety of outcomes depending on the reaction.
• Reduction, transamination, oxidative decarboxylation, and carboxylation/decarboxylation are all possible reactions.

The different types of reactions that pyruvate undergoes in a mammalian cell are:

• Reduction is the process in which a molecule gains electron. Under anaerobic conditions, pyruvate gets reduced to form lactate.
• Transamination is the process of transfer of amino group. The pyruvate can undergo transamination to form alanine.
• Under aerobic conditions, the pyruvate undergoes oxidative decarboxylation and gets converted into acetyl CoA.

Pyruvate can undergo carboxylation to form oxaloacetate.

• Pyruvate is the end product of glycolysis in aerobic circumstances.
• It can, however, be converted to lactate or ethanol under anaerobic conditions.
• Pyruvate can be reduced, transaminated, decarboxylated oxidatively, and carboxylated/decarboxylated.
• Pyruvate can also be decarboxylated in yeast to create acetaldehyde, which does not happen in human cells.
• Pyruvate decarboxylase is the enzyme that catalyses the process.

$Pyruvate\stackrel{pyruvatedecarboxylase}{\to }Acetaldehyde+C{O}_2$