Sn protoporphyrin

As described later, hemopexin interacts with a variety of heme analogs, two of which, Sn-protoporphyrin IX (SnPP) and Co-protoporphyrin IX (CoPP), helped clarify the mechanism of MT-1 gene regulation by hemopexin. SnPP-hemopexin interacts with the hemopexin receptor and the SnPP (an inhibitor of HO-1, (91)) enters the cell and induces HO-1 (92). In contrast, CoPP-hemopexin interacts with the receptor, but CoPP is not internalized. Interestingly, the mere occupancy of the receptor by hemopexin is sufficient to activate signaling pathways and consequent induction of MT-1 (90, 92, 93), whereas heme uptake is required for activation of HO-1 gene transcription (92, 93). 

Stevenson DK, Vreman HJ. Sn-protoporphyrin a consideration of the first clinical trial in human neonates. Pediatrics 1988 81(6) 881-2. 

Kappas A, Drummond GS, Manola T, Petmezaki S, Valaes T. Sn-protoporphyrin use in the management of hyperbilirubinemia in term newborns with direct Coombspositive ABO incompatibility. Pediatrics 1988 81(4) 485-97. 

Treatment of neonatal jaundice is usually by phototherapy. A decrease in bilirubin production in the neonatal period can also be achieved by inhibiting the rate-limiting enzyme of bilimbin formation from heme, namely, the heme oxygenase. A potent competitive inhibitor of heme oxygenase is the synthetic heme analogue tin (Sn" +) protoporphyrin. When administered parenterally, the tin protoporphyrin safely decreases bilimbin formation. Exchange transfusions also rapidly decrease plasma bilimbin levels. 

Ihrs Horse 2.6 HoLF cocrystallized with Sn-protoporphyrin IX to investigate heme binding 19... 

Tin(IV)-protoporphyrin (254), Ga-deuteroporphyrin (255), and Co-mesoporphyrin (256) complexes are potent inhibitors of heme oxygenase. The Sn(IV) complex significantly inhibits bilirubin production... 

Dichloro(protoporphyrin IX)tin(IV) (Sn-heme, 6) is undergoing clinical trials for the treatment of neonatal jaundice. It is a potent inhibi-... 

Figure 11.4. Molecular structure of the various water-soluble porphyrins and chlorins studied by photoelectrochemistry at the hquid/hquid interfaces chlorin e-6, protoporphyrin IX (protoIX), Sn(IV) mero-tetra(4-carboxyphenyl) porphyrin dichloiide (SnTPPC), Zn(II) mer >-tetra(Ai-methyl-4-pyridinium) porphyrin (ZnTMPyP) and Zn(II) meso-tetra. (4-sulphonatophenyl) porphyrin (ZnTPPS). The Zn(II) derivatives of TPPC have also been extenively studied.

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