View source for Precorrin-3B C17-methyltransferase

{{infobox enzyme
| Name       = precorrin-3B C17-methyltransferase
| EC_number  = 2.1.1.131
| CAS_number = 152787-64-9
| GO_code    = 0030789
| image      =
| width      = 
| caption    =  
}}
In [[enzymology]], '''precorrin-3B C17-methyltransferase''' ({{EC number|2.1.1.131}}) is an [[enzyme]] that [[catalysis|catalyzes]] the [[chemical reaction]]

:S-adenosyl-L-methionine + precorrin-3B <math>\rightleftharpoons</math> S-adenosyl-L-homocysteine + precorrin-4
:[[File:Precorrin-3B to Precorrin-4.svg|650px]]

The two [[substrate (biochemistry)|substrates]] of this enzyme are [[S-Adenosyl methionine|S-adenosyl methionine]] and [[precorrin 3B]], and its two [[product (chemistry)|products]] are [[S-adenosylhomocysteine]] and [[precorrin 4]].

This enzyme belongs to the family of [[transferase]]s, specifically those transferring one-carbon group methyltransferases.  The [[List of enzymes|systematic name]] of this enzyme class is '''S-adenosyl-L-methionine:precorrin-3B C17-methyltransferase'''. Other names in common use include '''precorrin-3 methyltransferase''', and '''CobJ'''.  This enzyme is part of the biosynthetic pathway to [[cobalamin biosynthesis|cobalamin]] (vitamin B<sub>12</sub>) in [[Aerobic organism|aerobic]] [[bacteria]] and during this step the [[macrocycle]] [[Ring expansion and ring contraction|ring-contracts]] so that the [[corrin]] core of the vitamin is formed.

==See also==
* [[Cobalamin biosynthesis]]

==References==
{{reflist|1}}
* {{cite journal | vauthors = Scott AI, Roessner CA, Stolowich NJ, Spencer JB, Min C, Ozaki SI | date = 1993 | title = Biosynthesis of vitamin B12. Discovery of the enzymes for oxidative ring contraction and insertion of the fourth methyl group | journal = FEBS Lett.  | volume = 331 | pages = 105&ndash;8  | pmid = 8405386 | doi = 10.1016/0014-5793(93)80306-F | issue = 1–2 | doi-access = free }}
* {{cite journal | vauthors = Debussche L, Thibaut D, Cameron B, Crouzet J, Blanche F | date = 1993 | title = Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans | journal = J. Bacteriol.  | volume = 175 | pages = 7430&ndash;40  | pmid = 8226690 | issue = 22 | pmc = 206888 }}

{{One carbon transferases}}
{{Enzymes}}
{{Portal bar|Biology|border=no}}

[[Category:EC 2.1.1]]
[[Category:Enzymes of unknown structure]]


{{2.1-enzyme-stub}}