ethanol metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving ethanol, CH3-CH2-OH, a colorless, water-miscible, flammable liquid produced by alcoholic fermentation. [GOC:ai, ISBN:0198506732]

Ethanol metabolism is a complex process that involves a series of enzymatic reactions to break down ethanol into less toxic byproducts. The process primarily occurs in the liver, where it is catalyzed by two main enzymes: alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH).

1. **ADH-mediated Oxidation:** The first step in ethanol metabolism involves the oxidation of ethanol to acetaldehyde by ADH. This reaction requires NAD+ as a cofactor and produces NADH. ADH exists in various isoforms, each with different affinities for ethanol.

2. **ALDH-mediated Oxidation:** Acetaldehyde, a highly reactive and toxic compound, is further oxidized to acetate by ALDH. This reaction also requires NAD+ as a cofactor and produces NADH. ALDH also exists in various isoforms, with different levels of activity and susceptibility to inhibition.

3. **Acetate Metabolism:** Acetate, the end product of ethanol metabolism, is relatively harmless and can be further metabolized in various ways. It can enter the citric acid cycle (Krebs cycle) to generate energy, be used for fatty acid synthesis, or be converted to carbon dioxide and water.

4. **Metabolic Pathways:** The relative contributions of ADH and ALDH in ethanol metabolism vary depending on factors such as genetics, age, and gender. In addition to ADH and ALDH, other enzymes, such as cytochrome P450 2E1 (CYP2E1), can also contribute to ethanol metabolism, particularly at high ethanol concentrations.

5. **Toxic Effects:** Ethanol metabolism can lead to several toxic effects, including liver damage, acetaldehyde accumulation, and increased oxidative stress. These effects are primarily due to the generation of reactive oxygen species (ROS) during ethanol metabolism and the accumulation of toxic intermediates like acetaldehyde.

The overall process of ethanol metabolism is tightly regulated to prevent the accumulation of toxic byproducts. However, excessive ethanol consumption can overwhelm these regulatory mechanisms, leading to various health problems.'
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Proteins (1)

Compounds (4)