Enzymes
UniProtKB help_outline | 4 proteins |
Enzyme class help_outline |
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GO Molecular Function help_outline |
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Reaction participants Show >> << Hide
- Name help_outline 8-O-methylsterigmatocystin Identifier CHEBI:18171 (CAS: 17878-69-2) help_outline Charge 0 Formula C19H14O6 InChIKeyhelp_outline JKUJKKGMOZDDJV-ZRNGKTOUSA-N SMILEShelp_outline [H][C@]12OC=C[C@@]1([H])c1c(O2)cc(OC)c2c1oc1cccc(OC)c1c2=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline O2 Identifier CHEBI:15379 (CAS: 7782-44-7) help_outline Charge 0 Formula O2 InChIKeyhelp_outline MYMOFIZGZYHOMD-UHFFFAOYSA-N SMILEShelp_outline O=O 2D coordinates Mol file for the small molecule Search links Involved in 2,709 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
reduced [NADPH—hemoprotein reductase]
Identifier
RHEA-COMP:11964
Reactive part
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- Name help_outline FMNH2 Identifier CHEBI:57618 (Beilstein: 6258176) help_outline Charge -2 Formula C17H21N4O9P InChIKeyhelp_outline YTNIXZGTHTVJBW-SCRDCRAPSA-L SMILEShelp_outline Cc1cc2Nc3c([nH]c(=O)[nH]c3=O)N(C[C@H](O)[C@H](O)[C@H](O)COP([O-])([O-])=O)c2cc1C 2D coordinates Mol file for the small molecule Search links Involved in 794 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline aflatoxin B1 Identifier CHEBI:2504 (CAS: 1162-65-8) help_outline Charge 0 Formula C17H12O6 InChIKeyhelp_outline OQIQSTLJSLGHID-WNWIJWBNSA-N SMILEShelp_outline [H][C@]12OC=C[C@@]1([H])c1c(O2)cc(OC)c2c3CCC(=O)c3c(=O)oc12 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CO2 Identifier CHEBI:16526 (Beilstein: 1900390; CAS: 124-38-9) help_outline Charge 0 Formula CO2 InChIKeyhelp_outline CURLTUGMZLYLDI-UHFFFAOYSA-N SMILEShelp_outline O=C=O 2D coordinates Mol file for the small molecule Search links Involved in 997 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,204 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline methanol Identifier CHEBI:17790 (Beilstein: 1098229; CAS: 67-56-1) help_outline Charge 0 Formula CH4O InChIKeyhelp_outline OKKJLVBELUTLKV-UHFFFAOYSA-N SMILEShelp_outline CO 2D coordinates Mol file for the small molecule Search links Involved in 45 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
oxidized [NADPH—hemoprotein reductase]
Identifier
RHEA-COMP:11965
Reactive part
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- Name help_outline FMN Identifier CHEBI:58210 Charge -3 Formula C17H18N4O9P InChIKeyhelp_outline ANKZYBDXHMZBDK-SCRDCRAPSA-K SMILEShelp_outline C12=NC([N-]C(C1=NC=3C(N2C[C@@H]([C@@H]([C@@H](COP(=O)([O-])[O-])O)O)O)=CC(=C(C3)C)C)=O)=O 2D coordinates Mol file for the small molecule Search links Involved in 804 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:35759 | RHEA:35760 | RHEA:35761 | RHEA:35762 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Characterization of the critical amino acids of an Aspergillus parasiticus cytochrome P-450 monooxygenase encoded by ordA that is involved in the biosynthesis of aflatoxins B1, G1, B2, and G2.
Yu J., Chang P.-K., Ehrlich K.C., Cary J.W., Montalbano B., Dyer J.M., Bhatnagar D., Cleveland T.E.
The conversion of O-methylsterigmatocystin (OMST) and dihydro-O-methylsterigmatocystin to aflatoxins B1, G1, B2, and G2 requires a cytochrome P-450 type of oxidoreductase activity. ordA, a gene adjacent to the omtA gene, was identified in the aflatoxin-biosynthetic pathway gene cluster by chromoso ... >> More
The conversion of O-methylsterigmatocystin (OMST) and dihydro-O-methylsterigmatocystin to aflatoxins B1, G1, B2, and G2 requires a cytochrome P-450 type of oxidoreductase activity. ordA, a gene adjacent to the omtA gene, was identified in the aflatoxin-biosynthetic pathway gene cluster by chromosomal walking in Aspergillus parasiticus. The ordA gene was a homolog of the Aspergillus flavus ord1 gene, which is involved in the conversion of OMST to aflatoxin B1. Complementation of A. parasiticus SRRC 2043, an OMST-accumulating strain, with the ordA gene restored the ability to produce aflatoxins B1, G1, B2, and G2. The ordA gene placed under the control of the GAL1 promoter converted exogenously supplied OMST to aflatoxin B1 in Saccharomyces cerevisiae. In contrast, the ordA gene homolog in A. parasiticus SRRC 2043, ordA1, was not able to carry out the same conversion in the yeast system. Sequence analysis revealed that the ordA1 gene had three point mutations which resulted in three amino acid changes (His-400-->Leu-400, Ala-143-->Ser-143, and Ile-528-->Tyr-528). Site-directed mutagenesis studies showed that the change of His-400 to Leu-400 resulted in a loss of the monooxygenase activity and that Ala-143 played a significant role in the catalytic conversion. In contrast, Ile-528 was not associated with the enzymatic activity. The involvement of the ordA gene in the synthesis of aflatoxins G1, and G2 in A. parasiticus suggests that enzymes required for the formation of aflatoxins G1 and G2 are not present in A. flavus. The results showed that in addition to the conserved heme-binding and redox reaction domains encoded by ordA, other seemingly domain-unrelated amino acid residues are critical for cytochrome P-450 catalytic activity. The ordA gene has been assigned to a new cytochrome P-450 gene family named CYP64 by The Cytochrome P450 Nomenclature Committee. << Less
Appl. Environ. Microbiol. 64:4834-4841(1998) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
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Enzymological evidence for separate pathways for aflatoxin B1 and B2 biosynthesis.
Bhatnagar D., Cleveland T.E., Kingston D.G.
Aflatoxins B1 (AFB1) and B2 (AFB2) are biologically active secondary metabolites of Aspergillus flavus and Aspergillus parasiticus. These toxins are synthesized by the fungi from pathway precursors: sterigmatocystin (ST)----O-methylsterigmatocystin (OMST)----AFB1; dihydrosterigmatocystin (DHST)--- ... >> More
Aflatoxins B1 (AFB1) and B2 (AFB2) are biologically active secondary metabolites of Aspergillus flavus and Aspergillus parasiticus. These toxins are synthesized by the fungi from pathway precursors: sterigmatocystin (ST)----O-methylsterigmatocystin (OMST)----AFB1; dihydrosterigmatocystin (DHST)----dihydro-O-methylsterigmatocystin (DHOMST)----AFB2. The late stages of AFB1 synthesis are carried out by two enzyme activities, a methyltransferase (MT) (ST----OMST), and an oxidoreductase (OR) (OMST----AFB1). Properties of the purified MT have been identified in a previous investigation [Bhatnagar et al. (1988) Prep. Biochem. 18, 321]. In the current study, the OR was partially purified (150-fold of specific activity) from fungal cell-free extracts and characterized with extended investigation of the late stages of AFB1 and AFB2 synthesis. Whole cells of an isolate of A. flavus (SRRC 141), which produce only AFB2, were able to produce AFB1 in ST and OMST feeding studies; the results suggested that the enzymes involved in AFB2 biosynthesis also carry out AFB1 synthesis. Substrate competition experiments carried out with the OR showed that an increasing concentration of either OMST or DHOMST in the presence of a fixed, nonsaturating concentration of either DHOMST or OMST, respectively, resulted in a decline in production of one aflatoxin (B1 or B2) with a corresponding increase in the synthesis of the other toxin (B2 or B1). OMST was a preferred substrate (Km, 1.2 microM) for the oxidoreductase as compared to DHOMST (Km, 13.4 microM). Similar, substrate competition experiments showed that ST (Km, 2.0 microM) was a preferred substrate over DHST (Km, 22.5 microM) for a homogeneous MT.(ABSTRACT TRUNCATED AT 250 WORDS) << Less
Biochemistry 30:4343-4350(1991) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.