Chlorophyllide-a oxygenase explained

Chlorophyllide-a oxygenase
Ec Number:	1.14.13.122
Cas Number:	216503-73-0

Chlorophyllide-a oxygenase, chlorophyllide a oxygenase, chlorophyll-b synthase, CAO) is an enzyme with systematic name chlorophyllide-a:oxygen 7-oxidoreductase.^{[1] [2] [3] [4]} This enzyme catalyses the following chemical reactions

(1) chlorophyllide a + O₂ + NADPH + H⁺

\rightleftharpoons 7-hydroxychlorophyllide a + H₂O + NADP⁺

(2) 7-hydroxychlorophyllide a + O₂ + NADPH + H⁺

\rightleftharpoons chlorophyllide b + 2 H₂O + NADP⁺

This enzyme contains a mononuclear iron centre and is part of the biosynthetic pathway to chlorophylls.^{[5] [6]}

See also

• Biosynthesis of chlorophylls

Notes and References

1. Espineda CE, Linford AS, Devine D, Brusslan JA . The AtCAO gene, encoding chlorophyll a oxygenase, is required for chlorophyll b synthesis in Arabidopsis thaliana . Proceedings of the National Academy of Sciences of the United States of America . 96 . 18 . 10507–11 . August 1999 . 10468639 . 17919 . 10.1073/pnas.96.18.10507 . 1999PNAS...9610507E . free .
2. Oster U, Tanaka R, Tanaka A, Rüdiger W . Cloning and functional expression of the gene encoding the key enzyme for chlorophyll b biosynthesis (CAO) from Arabidopsis thaliana . The Plant Journal . 21 . 3 . 305–10 . February 2000 . 10758481 . 10.1046/j.1365-313x.2000.00672.x . free .
3. Eggink LL, LoBrutto R, Brune DC, Brusslan J, Yamasato A, Tanaka A, Hoober JK . Synthesis of chlorophyll b: localization of chlorophyllide a oxygenase and discovery of a stable radical in the catalytic subunit . BMC Plant Biology . 4 . 5 . April 2004 . 15086960 . 406501 . 10.1186/1471-2229-4-5 . free .
4. Porra RJ, Schäfer W, Cmiel E, Katheder I, Scheer H . The derivation of the formyl-group oxygen of chlorophyll b in higher plants from molecular oxygen. Achievement of high enrichment of the 7-formyl-group oxygen from 18O2 in greening maize leaves . European Journal of Biochemistry . 219 . 1–2 . 671–9 . January 1994 . 8307032 . 10.1111/j.1432-1033.1994.tb19983.x . free .
5. Biosynthesis of chlorophylls from protoporphyrin IX . Willows . Robert D. . Natural Product Reports . 2003 . 20 . 6 . 327–341 . 10.1039/B110549N . 12828371.
6. 10.1007/s11120-006-9076-6 . Recent advances in chlorophyll biosynthesis . 2007 . Bollivar . David W. . Photosynthesis Research . 90 . 2 . 173–194 . 17370354 . 23808539 .