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EC 1.14.15.17 Details

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EC number

1.14.15.17

Accepted name

pheophorbide a oxygenase

Reaction

pheophorbide a + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = red chlorophyll catabolite + 2 oxidized ferredoxin [iron-sulfur] cluster (overall reaction);;(1a) pheophorbide a + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H⁺ + O₂ = epoxypheophorbide a + 2 oxidized ferredoxin [iron-sulfur] cluster + H₂O;;(1b) epoxypheophorbide a + H₂O = red chlorophyll catabolite (spontaneous)

Other name(s)

pheide a monooxygenase, pheide a oxygenase, PaO, PAO

Systematic name

pheophorbide-a,ferredoxin:oxygen oxidoreductase (biladiene-forming)

Comment

This enzyme catalyses a key reaction in chlorophyll degradation, which occurs during leaf senescence and fruit ripening in higher plants. The enzyme from Arabidopsis contains a Rieske-type iron-sulfur cluster [2] and requires reduced ferredoxin, which is generated either by NADPH through the pentose-phosphate pathway or by the action of photosystem I [4]. While still attached to this enzyme, the product is rapidly converted into primary fluorescent chlorophyll catabolite by the action of EC 1.3.7.12, red chlorophyll catabolite reductase [2,6]. Pheophorbide b acts as an inhibitor. In ¹⁸O₂ labelling experiments, only the aldehyde oxygen is labelled, suggesting that the other oxygen atom may originate from H₂O [1].

History

created 2007 as EC 1.14.12.20, transferred 2016 to EC 1.14.15.17

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.2 Acting on the aldehyde or oxo group of donors

1.3 Acting on the CH-CH group of donors

1.3.1 With NAD⁺ or NADP⁺ as acceptor

1.3.2 With a cytochrome as acceptor

1.3.3 With oxygen as acceptor

1.3.4 With a disulfide as acceptor

1.3.5 With a quinone or related compound as acceptor

1.3.7 With an iron-sulfur protein as acceptor

1.3.8 With a flavin as acceptor

1.3.98 With other, known, physiological acceptors

1.3.99 With unknown physiological acceptors

1.4 Acting on the CH-NH₂ group of donors

1.5 Acting on the CH-NH group of donors

1.6 Acting on NADH or NADPH

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.9 Acting on a heme group of donors

1.10 Acting on diphenols and related substances as donors

1.11 Acting on a peroxide as acceptor

1.12 Acting on hydrogen as donor

1.13 Acting on single donors with incorporation of molecular oxygen (oxygenases)

1.14 Acting on paired donors, with incorporation or reduction of molecular oxygen

1.14.1 With NADH or NADPH as one donor (deleted sub-subclass)

1.14.1.1 created 1961 as EC 1.99.1.1, transferred 1965 to EC 1.14.14.1, deleted 1972

1.14.1.2 created 1965, deleted 1972

1.14.1.3 created 1961 as EC 1.99.1.13, transferred 1965 to EC 1.14.1.3, deleted 1972

1.14.1.4 created 1965, deleted 1972

1.14.1.5 created 1965, deleted 1972

1.14.1.6 created 1961 as EC 1.99.1.7, transferred 1965 to EC 1.14.1.6, deleted 1972

1.14.1.7 created 1965, deleted 1972

1.14.1.8 created 1965, deleted 1972

1.14.1.9 created 1965, deleted 1972

1.14.1.10 created 1965, deleted 1972

1.14.1.11 created 1965, deleted 1972

1.14.2 With ascorbate as one donor (deleted sub-subclass)

1.14.3 With reduced pteridine as one donor (deleted sub-subclass)

1.14.11 With 2-oxoglutarate as one donor, and incorporation of one atom of oxygen into each donor

1.14.12 With NADH or NADPH as one donor, and incorporation of two atoms of oxygen into the other donor

1.14.13 With NADH or NADPH as one donor, and incorporation of one atom of oxygen into the other donor

1.14.14 With reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen into the other donor

1.14.15 With reduced iron-sulfur protein as one donor, and incorporation of one atom of oxygen into the other donor

1.14.15.1 camphor 5-monooxygenase

1.14.15.2 camphor 1,2-monooxygenase

1.14.15.3 alkane 1-monooxygenase

1.14.15.4 steroid 11β-monooxygenase

1.14.15.5 corticosterone 18-monooxygenase

1.14.15.6 cholesterol monooxygenase (side-chain-cleaving)

1.14.15.7 choline monooxygenase

1.14.15.8 steroid 15β-monooxygenase

1.14.15.9 spheroidene monooxygenase

1.14.15.10 (+)-camphor 6-endo-hydroxylase

1.14.15.11 pentalenic acid synthase

1.14.15.12 pimeloyl-[acyl-carrier protein] synthase

1.14.15.13 pulcherriminic acid synthase

1.14.15.14 methyl-branched lipid ω-hydroxylase

1.14.15.15 cholestanetriol 26-monooxygenase

1.14.15.16 vitamin D₃ 24-hydroxylase

1.14.15.17 pheophorbide a oxygenase

1.14.15.18 calcidiol 1-monooxygenase

1.14.15.19 C-19 steroid 1α-hydroxylase

1.14.15.20 heme oxygenase (biliverdin-producing, ferredoxin)

1.14.15.21 zeaxanthin epoxidase

1.14.15.22 vitamin D 1,25-hydroxylase

1.14.15.23 chloroacetanilide N-alkylformylase

1.14.15.24 β-carotene 3-hydroxylase

1.14.15.25 p-cymene methyl-monooxygenase

1.14.15.26 toluene methyl-monooxygenase

1.14.15.27 β-dihydromenaquinone-9 ω-hydroxylase

1.14.15.28 cholest-4-en-3-one 26-monooxygenase [(25R)-3-oxocholest-4-en-26-oate forming]

1.14.15.29 cholest-4-en-3-one 26-monooxygenase [(25S)-3-oxocholest-4-en-26-oate forming]

1.14.15.30 3-ketosteroid 9α-monooxygenase

1.14.15.31 2-hydroxy-5-methyl-1-naphthoate 7-hydroxylase

1.14.15.32 pentalenene oxygenase

1.14.15.33 pikromycin synthase

1.14.15.34 20-oxo-5-O-mycaminosyltylactone 23-monooxygenase

1.14.15.35 6-deoxyerythronolide B hydroxylase

1.14.15.36 sterol 14α-demethylase (ferredoxin)

1.14.15.37 luteothin monooxygenase

1.14.15.38 N,N-dimethyl phenylurea N-demethylase

1.14.15.39 epi-isozizaene 5-monooxygenase

1.14.16 With reduced pteridine as one donor, and incorporation of one atom of oxygen into the other donor

1.14.17 With reduced ascorbate as one donor, and incorporation of one atom of oxygen into the other donor

1.14.18 With another compound as one donor, and incorporation of one atom of oxygen into the other donor

1.14.19 With oxidation of a pair of donors resulting in the reduction of O₂ to two molecules of water

1.14.20 With 2-oxoglutarate as one donor, and the other dehydrogenated

1.14.21 With NADH or NADPH as one donor, and the other dehydrogenated

1.14.99 Miscellaneous

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.17 Acting on CH or CH₂ groups

1.18 Acting on iron-sulfur proteins as donors

1.19 Acting on reduced flavodoxin as donor

1.20 Acting on phosphorus or arsenic in donors

1.21 Catalysing the reaction X-H + Y-H = X-Y

1.21.1 With NAD⁺ or NADP⁺ as acceptor

1.21.3 With oxygen as acceptor

1.21.4 With a disulfide as acceptor

1.21.98 With other, known, physiological acceptors

1.21.99 With unknown physiological acceptors

1.22 Acting on halogen in donors

1.23 Reducing C-O-C group as acceptor

1.97 Other oxidoreductases

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)

3.1 Acting on ester bonds

3.2 Glycosylases

3.3 Acting on ether bonds

3.4 Acting on peptide bonds (peptidases)

3.5 Acting on carbon-nitrogen bonds, other than peptide bonds

3.6 Acting on acid anhydrides

3.7 Acting on carbon-carbon bonds

3.8 Acting on halide bonds

3.9 Acting on phosphorus-nitrogen bonds

3.10 Acting on sulfur-nitrogen bonds

3.10.1 Acting on sulfur-nitrogen bonds (only sub-subclass identified to date)

3.11 Acting on carbon-phosphorus bonds

3.12 Acting on sulfur-sulfur bonds

3.13 Acting on carbon-sulfur bonds

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Release 2023.1 (January 2023)