High pressure induced inactivation of ferrous cytochrome P-450 LM2 (IIB4) CO complex: evidence for the presence of two conformers in the oligomer.
The effect of high pressure on the spectral properties of cytochrome P-450 LM2(Fe2+)-CO complex was studied. The application of high pressure was shown to induce the conversion of cytochrome P-450 to P-420. In the solution when P-450 was oligomeric only about 65% of the total converted to P-420. The remaining portion of cytochrome P-450 was stable at pressures up to 6 kbar. When P-450 was incorporated into membranes or when it was succinylated, the proportion of the pressure sensitive fraction was slightly higher (about 75%). Dissociation of P-450 oligomers into monomers was made by addition of 0.2% Triton N-101. Monomers were the most sensitive to pressure; they could be completely converted to P-420. These results have been interpreted as evidence for the existence of two different conformers of P-450 LM2, which differ in pressure stability. Splitting between these two states appears to be a result of the oligomeric organization of cytochrome P-450 in solution and in the membrane.
Davydov
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DR
Institute de Biologie Phisico-Chimique, INSERM U310, Paris, France.
Knyushko
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TV
Hoa
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GH
D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D002248:Carbon Monoxide / Q000378:metabolism*; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry; D008081:Liposomes; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D010634:Phenobarbital / Q000494:pharmacology; D011312:Pressure; D011487:Protein Conformation; D011510:Proteolipids / Q000737:chemistry / Q000378:metabolism; D011817:Rabbits; D013053:Spectrophotometry; D013250:Steroid Hydroxylases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D013816:Thermodynamics
D065607:Cytochrome P-450 Enzyme Inhibitors; D008081:Liposomes; D011510:Proteolipids; C020485:proteoliposomes; D002248:Carbon Monoxide; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C050356:steroid 15-alpha-hydroxylase; D010634:Phenobarbital