Magnesium chelatase

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In enzymology, a magnesium chelatase (EC is an enzyme that catalyzes the chemical reaction

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

The 4 substrates of this enzyme are ATP, protoporphyrin IX, Mg2+, and H2O, whereas its 4 products are ADP, phosphate, Mg-protoporphyrin IX, and H+.

This enzyme belongs to the family of ligases, specifically those forming nitrogen-D-metal bonds in coordination complexes. The systematic name of this enzyme class is Mg-protoporphyrin IX magnesium-lyase. Other names in common use include protoporphyrin IX magnesium-chelatase, protoporphyrin IX Mg-chelatase, magnesium-protoporphyrin IX chelatase, magnesium-protoporphyrin chelatase, magnesium-chelatase, Mg-chelatase, and Mg-protoporphyrin IX magnesio-lyase. This enzyme participates in porphyrin and chlorophyll metabolism.


  • IUBMB entry for
  • BRENDA references for (Recommended.)
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  • Walker CJ, Weinstein JD (1991). "In vitro assay of the chlorophyll biosynthetic enzyme Mg-chelatase: resolution of the activity into soluble and membrane-bound fractions". Proc. Natl. Acad. Sci. U. S. A. 88: 5789&ndash, 93. PMID 11607197.
  • Walker CJ, Willows RD (Pt 2). "Mechanism and regulation of Mg-chelatase". Biochem. J. 327: 321&ndash, 33. PMID 9359397. Check date values in: |date= (help)
  • Al-Karadaghi S (2001). "Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase". J. Mol. Biol. 311: 111&ndash, 22. PMID 11469861.

External links

The CAS registry number for this enzyme class is 9074-88-8.

Gene Ontology (GO) codes