:Demethylspheroidene O-methyltransferase

{{Infobox enzyme

| Name = Demethylspheroidene O-methyltransferase

| EC_number = 2.1.1.210

| CAS_number =

| GO_code =

| image =

| width =

| caption =

}}

Demethylspheroidene O-methyltransferase ({{EC number|2.1.1.210}}, 1-hydroxycarotenoid O-methylase, 1-hydroxycarotenoid methylase, 1-HO-carotenoid methylase, CrtF) is an enzyme with systematic name S-adenosyl-L-methionine:demethylspheroidene O-methyltransferase.{{cite journal | vauthors = Badenhop F, Steiger S, Sandmann M, Sandmann G | title = Expression and biochemical characterization of the 1-HO-carotenoid methylase CrtF from Rhodobacter capsulatus | journal = FEMS Microbiology Letters | volume = 222 | issue = 2 | pages = 237–42 | date = May 2003 | pmid = 12770713 | doi = 10.1016/s0378-1097(03)00302-1 | doi-access = free }}{{cite journal | vauthors = Pinta V, Ouchane S, Picaud M, Takaichi S, Astier C, Reiss-Husson F | title = Characterization of unusual hydroxy- and ketocarotenoids in Rubrivivax gelatinosus: involvement of enzyme CrtF or CrtA | journal = Archives of Microbiology | volume = 179 | issue = 5 | pages = 354–62 | date = May 2003 | pmid = 12664193 | doi = 10.1007/s00203-003-0538-3 | s2cid = 30048505 }}{{cite journal | vauthors = Scolnik PA, Walker MA, Marrs BL | title = Biosynthesis of carotenoids derived from neurosporene in Rhodopseudomonas capsulata | journal = The Journal of Biological Chemistry | volume = 255 | issue = 6 | pages = 2427–32 | date = March 1980 | doi = 10.1016/S0021-9258(19)85909-4 | pmid = 7358679 | doi-access = free }} This enzyme catalyses the following chemical reaction

: S-adenosyl-L-methionine + demethylspheroidene $\backslash rightleftharpoons$ S-adenosyl-L-homocysteine + spheroidene

In Rhodopseudomonas capsulata and Rubrivivax gelatinosus the enzyme is involved in biosynthesis of spheroidene.