Information on EC 1.14.13.101 - senecionine N-oxygenase

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Tropane, piperidine and pyridine alkaloid biosynthesis

oxygenase, senecionine N-

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PA N-oxygenase

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PNO

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senecionine monooxygenase (N-oxide-forming)

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senecionine N-oxygenase

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SNO

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TjSNO

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senecionine + NADPH + H+ + O2 = senecionine N-oxide + NADP+ + H2O

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N-oxidation

oxidation

redox reaction

reduction

KEGG

MetaCyc

senecionine N-oxide biosynthesis

senecionine,NADPH:oxygen oxidoreductase (N-oxide-forming)

A flavoprotein. NADH cannot replace NADPH. While pyrrolizidine alkaloids of the senecionine and monocrotaline types are generally good substrates (e.g. senecionine, retrorsine and monocrotaline), the enzyme does not use ester alkaloids lacking an hydroxy group at C-7 (e.g. supinine and phalaenopsine), 1,2-dihydro-alkaloids (e.g. sarracine) or unesterified necine bases (e.g. senkirkine) as substrates [1]. Senecionine N-oxide is used by insects as a chemical defense: senecionine N-oxide is non-toxic, but it is bioactivated to a toxic form by the action of cytochrome P-450 oxidase when absorbed by insectivores.

220581-68-0

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atropine + NADPH + H+ + O2

atropine N-oxide + NADP+ + H2O

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-

?

atropine + NADPH + O2

atropine N-oxide + NADP+ + H2O

21% of the activity with monocrotaline

-

?

axillaridine + NADPH + H+ + O2

axillaridine N-oxide + NADP+ + H2O

-

-

?

axillaridine + NADPH + O2

axillaridine N-oxide + NADP+ + H2O

axillarine + NADPH + H+ + O2

axillarine N-oxide + NADP+ + H2O

-

-

?

axillarine + NADPH + O2

axillarine N-oxide + NADP+ + H2O

5 entries

cysteamine + NADPH + H+ + O2

cysteamine N-oxide + NADP+ + H2O

-

-

?

heliotrine + NADPH + H+ + O2

heliotrine N-oxide + NADP+ + H2O

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-

?

heliotrine + NADPH + O2

heliotrine N-oxide + NADP+ + H2O

6 entries

indicine + NADPH + H+ + O2

indicine N-oxide + NADP+ + H2O

-

-

?

indicine + NADPH + O2

indicine N-oxide + NADP+ + H2O

lycopsamine + NADPH + O2

lycopsamine N-oxide + NADP+ + H2O

monocrotaline + NADPH + H+ + O2

monocrotaline N-oxide + NADP+ + H2O

-

-

?

monocrotaline + NADPH + O2

monocrotaline N-oxide + NADP+ + H2O

6 entries

nicotine + NADPH + H+ + O2

nicotine N-oxide + NADP+ + H2O

-

-

?

phalaenopsine + NADPH + H+ + O2

phalaenopsine N-oxide + NADP+ + H2O

-

-

?

phalaenopsine + NADPH + O2

phalaenopsine N-oxide + NADP+ + H2O

19% of the activity with monocrotaline

-

?

retronecine + NADPH + H+ + O2

retronecine N-oxide + NADP+ + H2O

-

-

?

retrorsine + NADPH + H+ + O2

retrorsine N-oxide + NADP+ + H2O

-

-

?

retrorsine + NADPH + O2

retrorsine N-oxide + NADP+ + H2O

rinderine + NADPH + H+ + O2

rinderine N-oxide + NADP+ + H2O

-

-

?

rinderine + NADPH + O2

rinderine N-oxide + NADP+ + H2O

sarracine + NADPH + H+ + O2

sarracine N-oxide + NADP+ + H2O

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-

?

senecionine + NADPH + H+ + O2

senecionine N-oxide + NADP+ + H2O

2 entries

senecionine + NADPH + O2

senecionine N-oxide + NADP+ + H2O

7 entries

seneciphylline + NADPH + H+ + O2

seneciphylline N-oxide + NADP+ + H2O

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second best substrate

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?

seneciphylline + NADPH + O2

seneciphylline N-oxide + NADP+ + H2O

5 entries

senecivernine + NADPH + H+ + O2

senecivernine N-oxide + NADP+ + H2O

-

-

?

senecivernine + NADPH + O2

senecivernine N-oxide + NADP+ + H2O

triangularine + NADPH + O2

triangularine N-oxide + NADP+ + H2O

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60% of the activity with senecionine

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?

additional information

?

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10 entries

senecionine + NADPH + H+ + O2

senecionine N-oxide + NADP+ + H2O

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most efficient substrate

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?

senecionine + NADPH + O2

senecionine N-oxide + NADP+ + H2O

Q8MP06

-

-

?

seneciphylline + NADPH + H+ + O2

seneciphylline N-oxide + NADP+ + H2O

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second best substrate

-

?

additional information

?

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2 entries

FAD

2 entries

NADPH

5 entries

cytochrome c

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guanethidine

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enhances activity

Metyrapone

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enhances activity

n-octylamine

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activity of solubilized enzyme is 1.6fold increased by 0.5 mM n-octylamine

0.00983

atropine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.0186 - 0.284

heliotrine

0.0029 - 0.0125

monocrotaline

0.0013

NADPH

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pH 7.0, pH 37°C

0.8376

phalaenopsine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.00108 - 0.0048

senecionine

0.37

atropine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.12

heliotrine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.96

monocrotaline

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.13

phalaenopsine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.99

senecionine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

37.64

atropine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.454

heliotrine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

80.5

monocrotaline

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

0.155

phalaenopsine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

916.7

senecionine

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in 100 mM glycine/NaOH buffer pH 9.0, at 37°C

3.3

purified enzyme with senecionine as substrate

4.67

-

7

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7.5

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solubilized partially purified enzyme

8

assay at

9

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in potassium phosphate buffer (10 mM), Tris/HCl buffer (10 mM), and in glycine/NaOH buffer (100 mM)

37

assay at

40 - 45

42

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4.9

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determination on an Ampholine PAGplate pH 3.5-9.5 using a horizantal electrophoresis system

Amerila phaedra

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-

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UniProt

-

-

-

-

-

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Creatonotos transiens

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-

-

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Idea leuconoe

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no activity in Spodoptera littoralis

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-

-

-

-

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-

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membrane

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bound to

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additional information

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not a microsomal enzyme

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47793

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2 * 47793, calculated from amino acid sequence

51000

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4 * 51000, SDS-PAGE

91200

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gel filtration

200000

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gel filtration

homodimer

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2 * 47793, calculated from amino acid sequence

tetramer

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4 * 51000, SDS-PAGE

37

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20 min, solubilized enzyme is completely inactivated in absence of NADPH, preincubation the presence of NADPH has no effect

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Ni2+-NTA agarose column chromatography

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partial

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expressed in Escherichia coli BL21(DE3) cells

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expressing GgPNO without the signal peptide in at least a partially soluble and active form. Betaine is added to the medium and promotes its uptake by osmotic stress by sorbitol. Further improvements are achieved by coexpression with the Escherichia coli chaperones DnaK/DnaJ/GrpE by using the plasmid pRDKJG and by reducing the expression temperature to 4°C

expression in active form in Escherichia coli BL21

Q8MP06

653688

the heterologous expression results in the formation of an insoluble and inactive protein. Despite the finding that protein solubilization and subsequent renaturation results in an active protein, the specific activity remains low. Active SNO is detected by using an an Sf9 insect cell expression system, but the yield of protein is too low for further biochemical characterization. Using an alignment of senecionine N-oxygenase of Tyria jacobaeae and of flavin-dependent monooxygenase-like sequences of the dipteran species Drosophila melanogaster and Anopheles gambiae, several new flavin-dependent monooxygenase sequences of arctiids and other Lepidoptera are idenified

Q8MP06