Question

What is alcohol dehydrogenase (ADH) and nicotinamide adenine dinucleotide (NAD)? What role do they play in regards to the conversion of alcohol?

Answer 1

Alcohol dehydrogenases are the member of the dehydrogenase family. Dehydrogenase enzymes are the enzymes which remove the hydrogen atoms from the specific type of molecules. In other words, we can say that these enzymes oxidize a particular type of molecules mainly in the electron transport chain. As the name suggests, Alcohol dehydrogenase removes the hydrogen from alcohol molecules to convert them into aldehyde or ketone or acids depending on the extent of reduction.
NADs are the coenzyme with the nicotinamide and adenine as a backbone comes from the vitamin niacin, and it has two nucleotides so it is called dinucleotide. NAD plays an important role in metabolic pathways by accepting or donating electrons to the molecules. In the living cells, it exists as either NAD+ or NADH. NAD+ is an oxidized form whereas NADH is the reduced form of the NAD.
When we consume alcohol, it needs to oxidize completely to carbon dioxide. Alcohol cannot be directly converted to carbon dioxide. So first it gets converts to aldehyde or ketone with the help of alcohol dehydrogenase. During this conversion, alcohol dehydrogenase removes electrons which get accepted by the NAD.