hydroxyacid-oxoacid transhydrogenase, mitochondrial (HOT, Fe-containing alcohol dehydrogenase, ADHFe1, alcohol dehydrogenase iron-containing protein 1, ADHFE1)
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Function
- catalyzes the cofactor-independent reversible oxidation of gamma-hydroxybutyrate to succinic semialdehyde coupled to reduction of 2-ketoglutarate to D-2-hydroxyglutarate
- D,L-3-hydroxyisobutyrate & L-3-hydroxybutyrate are also substrates for ADHFE1 with 10-fold lower activities
(S)-3-hydroxybutanoate + 2-oxoglutarate
<-->
acetoacetate + (R)-2-hydroxyglutarate
2-oxoglutaric acid + 4-hydroxybutanoic acid
<-->
(R)-2-hydroxyglutaric acid + succinic semialdehyde
- KM=0.17 mM for gamma-hydroxybutyrate
- KM=1.2 mM for 2-ketoglutarate
- KM=0.12 mM for D-2-hydroxyglutarate
- KM=0.04 mM for succinic semialdehyde
- KM=0.8 mM for L-3-hydroxybutyrate
- Vmax=16 nmol/h/mg enzyme with gamma-hydroxybutyrate & 2-ketoglutarate as substrates
- Vmax=0.5 nmol/h/mg enzyme with succinic semialdehyde & D-2-hydroxyglutarate as substrates
- Vmax=1.8 nmol/h/mg enzyme with L-3-hydroxybutyrate & 2-ketoglutarate as substrates
- Optimum pH is 7.5
Structure
- belongs to the iron-containing alcohol dehydrogenase family, hydroxyacid-oxoacid transhydrogenase subfamily
Compartment
Alternative splicing
named isoforms=4
Expression
only expressed in adult liver