Sirohydrochlorin
{{Chembox
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| ImageFile=SirohydrochlorinCorr.png
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|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo= 65207-12-7
| PubChem= 196427
| ChEBI=18023
| KEGG = C05778
| ChemSpiderID = 16736728
| InChI=1S/C42H46N4O16/c1-41(17-39(59)60)23(5-9-35(51)52)29-14-27-21(11-37(55)56)19(3-7-33(47)48)25(43-27)13-26-20(4-8-34(49)50)22(12-38(57)58)28(44-26)15-31-42(2,18-40(61)62)24(6-10-36(53)54)30(46-31)16-32(41)45-29/h13-16,23-24,43-44H,3-12,17-18H2,1-2H3,(H,47,48)(H,49,50)(H,51,52)(H,53,54)(H,55,56)(H,57,58)(H,59,60)(H,61,62)/t23-,24-,41+,42+/m1/s1
| InChIKey = AVBHZKNQGDKVEA-ZTKUHGNGSA-N
| SMILES=C[C@@]1([C@@H](C2=NC1=CC3=NC(=CC4=C(C(=C(N4)C=C5C(=C(C(=C2)N5)CC(=O)O)CCC(=O)O)CCC(=O)O)CC(=O)O)[C@@]([C@@H]3CCC(=O)O)(C)CC(=O)O)CCC(=O)O)CC(=O)O
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|Section2={{Chembox Properties
| Formula=C42H46N4O16
| MolarMass=
| Appearance= yellow solid
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|Section3={{Chembox Hazards
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Sirohydrochlorin is a tetrapyrrole macrocyclic metabolic intermediate in the biosynthesis of sirohaem, the iron-containing prosthetic group in sulfite reductase enzymes. It is also the biosynthetic precursor to cofactor F430, an enzyme which catalyzes the release of methane in the final step of methanogenesis.{{cite journal|last1=Mucha|first1=Helmut|last2=Keller|first2=Eberhard|last3=Weber|first3=Hans|last4=Lingens|first4=Franz|last5=Trösch|first5=Walter|date=1985-10-07|title=Sirohydrochlorin, a precursor of factor F430 biosynthesis in Methanobacterium thermoautotrophicum|journal=FEBS Letters|volume=190|issue=1|pages=169–171|doi=10.1016/0014-5793(85)80451-8|doi-access=free}}
Structure
Sirohydrochlorin was first isolated in the early 1970s when it was shown to be the metal-free form of the prosthetic group in the ferredoxin-nitrite reductase from spinach.{{cite journal |doi=10.1073/pnas.71.3.612 |title=Siroheme: A New Prosthetic Group Participating in Six-Electron Reduction Reactions Catalyzed by Both Sulfite and Nitrite Reductases |year=1974 |last1=Murphy |first1=M. J. |last2=Siegel |first2=L. M. |last3=Tove |first3=S. R. |last4=Kamin |first4=H. |journal=Proceedings of the National Academy of Sciences |volume=71 |issue=3 |pages=612–616 |pmid=4595566 |pmc=388061 |bibcode=1974PNAS...71..612M |doi-access=free }} Its chemical identity was established by spectroscopy and by total synthesis.{{cite journal |doi=10.1021/ja00493a031 |title=Sirohydrochlorin. Prosthetic group of sulfite and nitrite reductases and its role in the biosynthesis of vitamin B12 |year=1978 |last1=Scott |first1=A. Ian |last2=Irwin |first2=Anthony J. |last3=Siegel |first3=Lewis M. |last4=Shoolery |first4=J. N. |journal=Journal of the American Chemical Society |volume=100 |issue=25 |pages=7987–7994 }}{{cite journal |doi=10.1039/C39780000150 |title=Biosynthesis of vitamin B12: Proof of A-B structure for sirohydrochlorin by its specific incorporation into cobyrinic acid |year=1978 |last1=Battersby |first1=Alan R. |last2=McDonald |first2=Edward |last3=Thompson |first3=Mervyn |last4=Bykhovsky |first4=Vladimir Ya. |journal=Journal of the Chemical Society, Chemical Communications |issue=3 |pages=150 }}{{cite journal |doi=10.1039/C39850001061 |title=Syntheses relevant to vitamin B12 biosynthesis: Synthesis of sirohydrochlorin and of its octamethyl ester |year=1985 |last1=Block |first1=Michael H. |last2=Zimmerman |first2=Steven C. |last3=Henderson |first3=Graeme B. |last4=Turner |first4=Simon P. D. |last5=Westwood |first5=Steven W. |last6=Leeper |first6=Finian J. |last7=Battersby |first7=Alan R. |journal=Journal of the Chemical Society, Chemical Communications |issue=16 |pages=1061 }}
Biosynthesis
Sirohydrochlorin is derived from a tetrapyrrolic structural framework created by the enzymes deaminase and cosynthetase which transform aminolevulinic acid via porphobilinogen and hydroxymethylbilane to uroporphyrinogen III. The latter is the first macrocyclic intermediate common to haem, chlorophyll, sirohaem and vitamin B12. Uroporphyrinogen III is subsequently transformed by the addition of two methyl groups to form dihydrosirohydrochlorin and this is oxidised by precorrin-2 dehydrogenase to give sirohydrochlorin.{{cite journal |doi=10.1039/B002635M |title=Tetrapyrroles: The pigments of life: A Millennium review |year=2000 |last1=Battersby |first1=Alan R. |journal=Natural Product Reports |volume=17 |issue=6 |pages=507–526 |pmid=11152419 }}
See also
- Sirohydrochlorin ferrochelatase an enzyme that catalyzes insertion of iron to form siroheme.
- Sirohydrochlorin cobaltochelatase an enzyme that catalyzes insertion of cobalt.