IUBMB Enzyme Nomenclature


Accepted name: magnesium chelatase

Reaction: ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+

For diagram of reaction click here (heme and chlorophyll biosynthesis).

Other name(s): protoporphyrin IX magnesium-chelatase; protoporphyrin IX Mg-chelatase; magnesium-protoporphyrin IX chelatase; magnesium-protoporphyrin chelatase; magnesium-chelatase; Mg-chelatase; Mg-protoporphyrin IX magnesio-lyase

Systematic name: Mg-protoporphyrin IX magnesium-lyase

Comments: This is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9074-88-8


1. Walker, C.J. and Weinstein, J.D. In vitro assay of the chlorophyll biosynthetic enzyme Mg-chelatase: resolution of the activity into soluble and membrane-bound fractions. Proc. Natl. Acad. Sci. USA 88 (1991) 5789-5793. [PMID: 11607197]

2. Walker, C.J. and Willows, R.D. Mechanism and regulation of Mg-chelatase. Biochem. J. 327 (1997) 321-333. [PMID: 9359397]

3. Fodje, M.N., Hansson, A., Hansson, M., Olsen, J.G., Gough, S., Willows, R.D. and Al-Karadaghi, S. Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase. J. Mol. Biol. 311 (2001) 111-122. [PMID: 11469861]

[EC created 2003]

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