KEGG ENZYME: 4.99.1.10

Entry
EC 4.99.1.10                Enzyme                                 
Name

magnesium dechelatase;
SGR (gene name);
SGRL (gene name);
Mg-dechelatase

Class

Lyases;
Other lyases;
Sole sub-subclass for lyases that do not belong in the other subclasses

Sysname

chlorophyll a magnesium lyase

Reaction(IUBMB)
(1) chlorophyll a + 2 H+ = pheophytin a + Mg2+ [RN:R08584];
(2) chlorophyllide a + 2 H+ = pheophorbide a + Mg2+ [RN:R09033]
Reaction(KEGG) Substrate Product Comment

Inhibited by Ca2+, Mg2+ and especially Hg2+. SGR has very low activity with chlorophyllide a and none with chlorophyll b. It acts on chlorophyll a both in its free form and in protein complex. SGRL, on the other hand, is more active with chlorophyllide a than with chlorophyll a. The magnesium formed is scavenged by MCS (metal-chelating substance).

History

EC 4.99.1.10 created 2017

Pathway
ec00860   Porphyrin and chlorophyll metabolism
ec01110   Biosynthesis of secondary metabolites
Orthology
K22013   magnesium dechelatase
Genes  » show all
Reference   Authors

Tang L, Okazawa A, Fukusaki E, Kobayashi A

  Title

Removal of magnesium by Mg-dechelatase is a major step in the chlorophyll-degrading pathway in Ginkgo biloba in the process of autumnal tints.

  Journal Reference

2

  Authors

Costa, M.A., Civello, P.M., Chaves, A.R. and Martinez, G.A.

  Title

Characterization of Mg-dechelatase activity obtained from Fragaria x ananassa fruit.

  Journal

Plant Physiol Biochem 40:111-118 (2002)

Reference   Authors

Wang T, Quisenberry SS, Ni X, Tolmay V

  Title

Enzymatic chlorophyll degradation in wheat near-isogenic lines elicited by cereal aphid (Homoptera: Aphididae) feeding.

  Journal Reference   Authors

Suzuki T, Kunieda T, Murai F, Morioka S, Shioi Y

  Title

Mg-dechelation activity in radish cotyledons with artificial and native substrates, Mg-chlorophyllin a and chlorophyllide a.

  Journal Reference

5

  Authors

Kunieda, T., Amano, T. and Shioi, Y.

  Title

Search for chlorophyll degradation enzyme, Mg-dechelatase, from extracts of Chenopodium album with native and artificial substrates.

  Journal

Plant Sci 169:177-183 (2005)

Reference   Authors

Shimoda Y, Ito H, Tanaka A

  Title

Arabidopsis STAY-GREEN, Mendel’s Green Cotyledon Gene, Encodes Magnesium-Dechelatase.

  Journal   Sequence Other DBs
ExPASy – ENZYME nomenclature database:  4.99.1.10

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