4-Hydroxybutyrate dehydrogenase

Enzyme involved in the metabolism of gamma-hydroxybutyrate

4-Hydroxybutyrate dehydrogenase is an enzyme that plays a crucial role in the metabolism of gamma-hydroxybutyrate (GHB), a naturally occurring neurotransmitter and psychoactive drug. This enzyme is responsible for the oxidation of 4-hydroxybutyrate to succinic semialdehyde, which is a key step in the metabolic pathway of GHB.

Structure

4-Hydroxybutyrate dehydrogenase is a member of the short-chain dehydrogenase/reductase (SDR) family of enzymes. It typically functions as a homotetramer, meaning it is composed of four identical subunits. Each subunit contains a NAD+ binding domain, which is essential for its enzymatic activity.

Function

The primary function of 4-hydroxybutyrate dehydrogenase is to catalyze the conversion of 4-hydroxybutyrate to succinic semialdehyde. This reaction is part of the GABA shunt, a metabolic pathway that links the metabolism of gamma-aminobutyric acid (GABA) with the tricarboxylic acid cycle (TCA cycle). The enzyme uses NAD+ as a cofactor, which is reduced to NADH during the reaction.

Biological significance

4-Hydroxybutyrate dehydrogenase is important for maintaining the balance of GHB and its metabolites in the body. GHB is both a neurotransmitter and a drug of abuse, and its levels are tightly regulated. The enzyme's activity ensures that excess GHB is metabolized efficiently, preventing potential toxic effects.

Clinical relevance

Alterations in the activity of 4-hydroxybutyrate dehydrogenase can have significant clinical implications. Deficiencies in this enzyme may lead to the accumulation of GHB, which can result in neurological disorders and metabolic diseases. Understanding the function and regulation of this enzyme is important for developing therapeutic strategies for conditions associated with GHB dysregulation.

Related pages

• Gamma-hydroxybutyrate
• Short-chain dehydrogenase/reductase
• GABA shunt
• Tricarboxylic acid cycle

Gallery

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  Structure of 4-hydroxybutyrate dehydrogenase