Methylsterol monooxygenase

Methylsterol monooxygenase
Identifiers
EC no.	1.14.13.72
CAS no.	37256-80-7
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

Methylsterol monooxygenase (EC 1.14.13.72, methylsterol hydroxylase, 4-methylsterol oxidase, 4,4-dimethyl-5alpha-cholest-7-en-3beta-ol,hydrogen-donor:oxygen oxidoreductase (hydroxylating)) is an enzyme with systematic name 4,4-dimethyl-5alpha-cholest-7-en-3beta-ol,NAD(P)H:oxygen oxidoreductase (hydroxylating). ^{[1] [2] [3] [4] [5] [6] [7]} This enzyme catalyses the following chemical reaction

4,4-dimethyl-5alpha-cholest-7-en-3beta-ol + 3 NAD(P)H + 3 H⁺ + 3 O₂${\displaystyle \rightleftharpoons }$ 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carboxylate + 3 NAD(P)⁺ + 4 H₂O (overall reaction)

(1a) 4,4-dimethyl-5alpha-cholest-7-en-3beta-ol + NAD(P)H + H⁺ + O₂${\displaystyle \rightleftharpoons }$ 4beta-hydroxymethyl-4alpha-methyl-5alpha-cholest-7-en-3beta-ol + NAD(P)⁺ + H₂O

(1b) 4beta-hydroxymethyl-4alpha-methyl-5alpha-cholest-7-en-3beta-ol + NAD(P)H + H⁺ + O₂${\displaystyle \rightleftharpoons }$ 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carbaldehyde + NAD(P)⁺ + 2 H₂O

(1c) 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carbaldehyde + NAD(P)H + H⁺ + O₂${\displaystyle \rightleftharpoons }$ 3beta-hydroxy-4beta-methyl-5alpha-cholest-7-ene-4alpha-carboxylate + NAD(P)⁺ + H₂O

Methylsterol monooxygenase requires cytochrome b5.

References

1. Rahier A, Smith M, Taton M (July 1997). "The role of cytochrome b5 in 4alpha-methyl-oxidation and C5(6) desaturation of plant sterol precursors". Biochemical and Biophysical Research Communications. 236 (2): 434–7. doi:10.1006/bbrc.1997.6974. PMID   9240456.
2. Pascal S, Taton M, Rahier A (June 1993). "Plant sterol biosynthesis. Identification and characterization of two distinct microsomal oxidative enzymatic systems involved in sterol C4-demethylation". The Journal of Biological Chemistry. 268 (16): 11639–54. PMID   8505296.
3. Kawata S, Trzaskos JM, Gaylor JL (March 1986). "Affinity chromatography of microsomal enzymes on immobilized detergent-solubilized cytochrome b5". The Journal of Biological Chemistry. 261 (8): 3790–9. PMID   3949790.
4. Fukushima H, Grinstead GF, Gaylor JL (May 1981). "Total enzymic synthesis of cholesterol from lanosterol. Cytochrome b5-dependence of 4-methyl sterol oxidase". The Journal of Biological Chemistry. 256 (10): 4822–6. PMID   7228857.
5. Brady DR, Crowder RD, Hayes WJ (November 1980). "Mixed function oxidases in sterol metabolism. Source of reducing equivalents". The Journal of Biological Chemistry. 255 (22): 10624–9. PMID   7430141.
6. Gaylor JL, Mason HS (October 1968). "Investigation of the component reactions of oxidative sterol demethylation. Evidence against participation of cytochrome P-450". The Journal of Biological Chemistry. 243 (19): 4966–72. PMID   4234469.
7. Miller WL, Kalafer ME, Gaylor JL, Delwiche CV (September 1967). "Investigation of the component reactions of oxidative sterol demethylation. Study of the aerobic and anaerobic processes". Biochemistry. 6 (9): 2673–8. doi:10.1021/bi00861a005. PMID   4383278.

External links

• Methylsterol+monooxygenase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)