Enzymes
| UniProtKB help_outline | 2 proteins |
Reaction participants Show >> << Hide
- Name help_outline 25-hydroxy-24-oxocalciol Identifier CHEBI:47805 (Beilstein: 5628504; CAS: 74886-61-6) help_outline Charge 0 Formula C27H42O3 InChIKeyhelp_outline DDZHNKIBJQESJA-AHMPPUFCSA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])\C(CCC[C@]12C)=C\C=C1\C[C@@H](O)CCC1=C)[C@H](C)CCC(=O)C(C)(C)O 2D coordinates Mol file for the small molecule Search links Involved in 3 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 9,176 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 2,648 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
reduced [adrenodoxin]
Identifier
RHEA-COMP:9998
Reactive part
help_outline
- Name help_outline [2Fe-2S]1+ Identifier CHEBI:33738 Charge 1 Formula Fe2S2 InChIKeyhelp_outline MAGIRAZQQVQNKP-UHFFFAOYSA-N SMILEShelp_outline S1[Fe]S[Fe+]1 2D coordinates Mol file for the small molecule Search links Involved in 236 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline (1S)-1,25-dihydroxy-24-oxocalciol Identifier CHEBI:47812 (Beilstein: 6005336; CAS: 76338-50-6) help_outline Charge 0 Formula C27H42O4 InChIKeyhelp_outline BWFQMABKLLTETH-YGQRWWDYSA-N SMILEShelp_outline [H][C@@]1(CC[C@@]2([H])\C(CCC[C@]12C)=C\C=C1\C[C@@H](O)C[C@H](O)C1=C)[C@H](C)CCC(=O)C(C)(C)O 2D coordinates Mol file for the small molecule Search links Involved in 3 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 6,048 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
oxidized [adrenodoxin]
Identifier
RHEA-COMP:9999
Reactive part
help_outline
- Name help_outline [2Fe-2S]2+ Identifier CHEBI:33737 Charge 2 Formula Fe2S2 InChIKeyhelp_outline XSOVBBGAMBLACL-UHFFFAOYSA-N SMILEShelp_outline S1[Fe+]S[Fe+]1 2D coordinates Mol file for the small molecule Search links Involved in 236 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:49068 | RHEA:49069 | RHEA:49070 | RHEA:49071 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Expression of human CYP27B1 in Escherichia coli and characterization in phospholipid vesicles.
Tang E.K.Y., Tieu E.W., Tuckey R.C.
CYP27B1 is a mitochondrial cytochrome P450 that catalyses the hydroxylation of 25-hydroxyvitamin D3 at the C1α-position to give the hormonally active form of vitamin D3, 1α,25-dihydroxyvitamin D3. We successfully expressed human CYP27B1 in Escherichia coli and partially purified this labile enzyme ... >> More
CYP27B1 is a mitochondrial cytochrome P450 that catalyses the hydroxylation of 25-hydroxyvitamin D3 at the C1α-position to give the hormonally active form of vitamin D3, 1α,25-dihydroxyvitamin D3. We successfully expressed human CYP27B1 in Escherichia coli and partially purified this labile enzyme and carried out a detailed characterization of its kinetic properties in a reconstituted membrane environment. The phospholipid concentration did not affect the enzyme activity in the vesicle-reconstituted system, although it was influenced by the phospholipid composition, with the addition of cardiolipin lowering the K(m) for 25-hydroxyvitamin D3. These data are consistent with the enzyme accessing substrate from the hydrophobic domain of the vesicle membrane. Cardiolipin also caused the appearance of inhibition of activity at high substrate concentrations. This substrate inhibition fitted a model for one catalytic and two inhibitory sites on the enzyme for the binding of substrate. The K(m) for human adrenodoxin was observed to decrease with decreasing substrate concentration, with the catalytic efficiency (k(cat) /K(m) ) being largely independent of adrenodoxin concentration. Human CYP27B1 was also active on 25-hydroxyvitamin D(2) and on intermediates of the CYP24A1-mediated inactivation pathway, 24R,25-dihydroxyvitamin D3, 24-oxo-25-hydroxyvitamin D3 and 24-oxo-23,25-dihydroxyvitamin D3, with all these substrates showing comparable k(cat) values of 50-71 min(-1) , similar to 25-hydroxyvitamin D3. The latter two substrates gave higher K(m) values than that for 25-hydroxy-vitamin D3. The present study shows that human CYP27B1 can be partially purified in an active form with the enzyme displaying high activity towards a range of substrates in a phospholipid vesicle-reconstituted system that mimics the inner-mitochondrial membrane. << Less
FEBS J. 279:3749-3761(2012) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.