Dihydrosirohydrochlorin

Dihydrosirohydrochlorin is one of several naturally occurring tetrapyrrole macrocyclic metabolic intermediates in the biosynthesis of vitamin B₁₂ (cobalamin). Its oxidised form, sirohydrochlorin, is precursor to sirohaem, the iron-containing prosthetic group in sulfite reductase enzymes. Further biosynthetic transformations convert sirohydrochlorin to cofactor F430 for an enzyme which catalyzes the release of methane in the final step of methanogenesis.

Dihydrosirohydrochlorin

Names
Other names precorrin 2
Identifiers
CAS Number	82542-92-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:50602
ChemSpider	26333172
KEGG	C02463
MeSH	15,23-dihydrosirohydrochlorin
PubChem CID	5280516
InChI InChI=1S/C42H48N4O16/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/h14-16,23-24,43-44,46H,3-13,17-18H2,1-2H3,(H,47,48)(H,49,50)(H,51,52)(H,53,54)(H,55,56)(H,57,58)(H,59,60)(H,61,62)/b29-14-,30-16-,31-15-/t23-,24-,41+,42+/m1/s1 Key: CSWLXNNNLVVXKD-ZIBVGKFXSA-N
SMILES CC1(C(C2=CC3=NC(=CC4=C(C(=C(N4)CC5=C(C(=C(N5)C=C1N2)CC(=O)O)CCC(=O)O)CCC(=O)O)CC(=O)O)C(C3(C)CC(=O)O)CCC(=O)O)CCC(=O)O)CC(=O)O
Properties
Chemical formula	C42H48N4O16
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Biosynthesis

Dihydrosirohydrochlorin 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.

See also

• Cobalamin biosynthesis
• Sirohydrochlorin
• Precorrin-2 dehydrogenase