Reaction: a 3β-hydroxysteroid-4α-carboxylate + NAD(P)+ = a 3-oxosteroid + CO2 + NAD(P)H
For diagram of reaction click here
Other name(s): 3β-hydroxy-4β-methylcholestenecarboxylate 3-dehydrogenase (decarboxylating); 3β-hydroxy-4β-methylcholestenoate dehydrogenase; sterol 4α-carboxylic decarboxylase; sterol-4 -carboxylate 3-dehydrogenase (decarboxylating) (ambiguous); ERG26 (gene name); NSDHL (gene name).
Systematic name: 3β-hydroxysteroid-4α-carboxylate:NAD(P)+ 3-oxidoreductase (decarboxylating)
Comments: The enzyme catalyses the decarboxylation of the C-4 carbon and the dehydrogenation of a 3β hydroxyl at the C-3 carbon of 3β-hydroxysteroid-4α-carboxylates. It is involved in zymosterol and cholesterol biosynthesis.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 71822-23-6
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2. Rahimtula, A.D. and Gaylor, J.L. Partial purification of a microsomal sterol 4α-carboxylic acid decarboxylase. J. Biol. Chem. 247 (1972) 9-15. [PMID: 4401584]
3. Gachotte, D., Barbuch, R., Gaylor, J., Nickel, E. and Bard, M. Characterization of the Saccharomyces cerevisiae ERG26 gene encoding the C-3 sterol dehydrogenase (C-4 decarboxylase) involved in sterol biosynthesis. Proc. Natl. Acad. Sci. USA 95 (1998) 13794-13799. [PMID: 9811880]
4. Caldas, H. and Herman, G.E. NSDHL, an enzyme involved in cholesterol biosynthesis, traffics through the Golgi and accumulates on ER membranes and on the surface of lipid droplets. Hum. Mol. Genet. 12 (2003) 2981-2991. [PMID: 14506130]