ENZYME

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ENZYME entry: EC 1.17.99.3

Accepted Name

3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholestanoyl-CoA 24-hydroxylase.

Alternative Name(s)

3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholestan-26-oate 24-hydroxylase.

3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholestanoyl-CoA oxidase.

THC-CoA oxidase.

THCA-CoA oxidase.

Trihydroxycoprostanoyl-CoA oxidase.

Reaction catalysed

(25R)-3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholestan-26-oyl-CoA + H(2)O + acceptor <=> (24R,25R)-3-alpha,7-alpha,12-alpha,24-tetrahydroxy-5-beta-cholestan-26-oyl-CoA + reduced acceptor

Comment(s)

Requires ATP.
The reaction in mammals possibly involves dehydrogenation to give a 24(25)-double bond followed by hydration.
However, in amphibians such as the Oriental fire-bellied toad (Bombina orientalis), it is probable that the product is formed via direct hydroxylation of the saturated side chain of (25R)-3-alpha,7- alpha,12-alpha-trihydroxy-5-beta-cholestan-26-oate and not via hydration of a 24(25) double bond.
In microsomes, the free acid is preferred to the coenzyme A ester, whereas in mitochondria, the coenzyme A ester is preferred to the free-acid form of the substrate.

Cross-references

BRENDA

1.17.99.3

EC2PDB

1.17.99.3

ExplorEnz

1.17.99.3

PRIAM enzyme-specific profiles

1.17.99.3

KEGG Ligand Database for Enzyme Nomenclature

1.17.99.3

IUBMB Enzyme Nomenclature