Final answer:
The alcohol dehydrogenase pathway is the primary metabolic process for alcohol in the liver. It involves the oxidation of ethanol to acetaldehyde, followed by the further metabolism of acetaldehyde to acetate through ALDH. This detoxifying pathway is significant in human health and yeast fermentation processes.
Step-by-step explanation:
Alcohol Dehydrogenase Pathway of Alcohol Metabolism
The alcohol dehydrogenase pathway is a significant metabolic route where ethanol from alcoholic beverages is processed in the liver. Around 80 to 90% of the ethanol taken up by the liver is metabolized through this system. The key enzyme, alcohol dehydrogenase, facilitates the oxidation of ethanol to acetaldehyde, producing NADH and an H+ ion as byproducts. Acetaldehyde is highly toxic and is swiftly metabolized by the enzyme acetaldehyde dehydrogenase (ALDH), which converts acetaldehyde into acetate, a harmless molecule.
The process of alcohol metabolism starts with the conversion of ethanol to acetaldehyde, a zeroth-order reaction that indicates the rate of reaction is constant and does not depend on the concentration of ethanol. At high concentrations of ethanol, the pathway's rate stays constant due to the enzyme's saturation level. Further oxidation of acetaldehyde by ALDH results in acetate, which is less toxic and can be further metabolized by the body.
The pathway is crucial for detoxifying the body from ethanol and is also of importance in yeast cells during the fermentation process, albeit with the reverse reaction where acetaldehyde is reduced to ethanol. However, the tolerance level for alcohol in yeast is variable, generally ranging between 5 percent to 21 percent alcohol by volume, depending on both the yeast strain and the environmental conditions.