Siroheme

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Structure of siroheme

Siroheme (or sirohaem) is a heme-like prosthetic group used by some enzymes to accomplish the six-electron reduction of sulfur and nitrogen.[1] Siroheme is synthesized from uroporphyrinogen III, a heme and vitamin B12 precursor.[2] It plays a major role in the sulfur assimilation pathway: converting sulfite to a biologically useful sulfide, which can be incorporated into the organic compound homocysteine.[3]

See also

References

  1. ↑ Matthew J. Murphy; et al. (1974). "Siroheme: A New Prosthetic Group Participating in Six-Electron Reduction Reactions Catalyzed by Both Sulfite and Nitrite Reductases". PNAS 71 (3): 612–616. doi:10.1073/pnas.71.3.612. PMC 388061. PMID 4595566. 
  2. ↑ Jorgen Hansen; et al. (1997). "Siroheme biosynthesis in Saccharomyces cerevisiae requires the products of both MET1 and MET8 genes". FEBS Letters 401 (1): 20–24. doi:10.1016/S0014-5793(96)01423-8. PMID 9003798. 
  3. ↑ Dominique Thomas; Yolande Surdin-Kerjan (1997). "Metabolism of sulfur amino acids in Saccharomyces cerevisiae". Microbiology and Molecular Biology Reviews 61 (4): 503–532. PMC 232622. PMID 9409150. 
Types of tetrapyrroles
Bilanes
(Linear)
Phytobilins
  • Phytochromobilin
Phycobilins
Macrocycle
Phytoporphyrins
Reduced
porphyrins
Porphyrinogens
  • Chlorophyllide (a, b)
  • Chlorophyll (a, b)
  • Phaeophytin (a, b)
  • Bacteriochlorophyll c
Bacteriochlorins
  • Bacteriochlorophyll a
Isobacteriochlorins
Corphins
  • Biochemical families: carbohydrates
    • alcohols
    • glycoproteins
    • glycosides
  • lipids
    • eicosanoids
    • fatty acids / intermediates
    • phospholipids
    • sphingolipids
    • steroids
  • nucleic acids
    • constituents / intermediates
  • proteins
    • Amino acids / intermediates
  • tetrapyrroles / intermediates
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