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EC 1.21.98.3 Details
show Brenda entryEC number
1.21.98.3
Accepted name
anaerobic magnesium-protoporphyrin IX monomethyl ester cyclase
Reaction
magnesium-protoporphyrin IX 13-monomethyl ester + 3 S-adenosyl-L-methionine + H2O = 3,8-divinyl protochlorophyllide a + 3 5′-deoxyadenosine + 3 L-methionine (overall reaction);;(1a) magnesium-protoporphyrin IX 13-monomethyl ester + S-adenosyl-L-methionine + H2O = 131-hydroxy-magnesium-protoporphyrin IX 13-monomethyl ester + 5′-deoxyadenosine + L-methionine;;(1b) 131-hydroxy-magnesium-protoporphyrin IX 13-monomethyl ester + S-adenosyl-L-methionine = 131-oxo-magnesium-protoporphyrin IX 13-monomethyl ester + 5′-deoxyadenosine + L-methionine;;(1c) 131-oxo-magnesium-protoporphyrin IX 13-monomethyl ester + S-adenosyl-L-methionine = 3,8-divinyl protochlorophyllide a + 5′-deoxyadenosine + L-methionine
Other name(s)
bchE (gene name),
MPE cyclase (ambiguous)
Systematic name
magnesium-protoporphyrin-IX 13-monomethyl ester,S-adenosyl-L-methionine:H2O oxidoreductase (hydroxylating)
Comment
This radical AdoMet enzyme participates in the biosynthesis of chlorophyllide a in anaerobic bacteria, catalysing the formation of an isocyclic ring. Contains a [4Fe-4S] cluster and a cobalamin cofactor. The same transformation is achieved in aerobic organisms by the oxygen-dependent EC 1.14.13.81, magnesium-protoporphyrin IX monomethyl ester (oxidative) cyclase. Some facultative phototrophic bacteria, such as Rubrivivax gelatinosus, possess both enzymes.
History
created 2016
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1 Oxidoreductases
1.1 Acting on the CH-OH group of donors
1.6.5.1 created 1961, deleted 1965
