Biophysics of structure and mechanism

, Volume 9, Issue 1, pp 29–34 | Cite as

Absorption spectra of highly purified liver microsomal cytochrome P-450 in non-equilibrium conformational states at low temperatures

  • S. Greschner


Absorption spectra of highly purified liver microsomal cytochrome P-450 in non-equilibrium states were obtained at 77 K by reduction with trapped electrons, formed by gamma-irradiation of the water-glycerol matrix. In contrast to the equilibrium form of ferrous cytochrome P-450 with the heme iron in the high-spin state the non-equilibrium ferrous state has a low-spin heme iron. The absorption spectrum of the non-equilibrium ferrous cytochrome P-450 is characterized by two bands at 564 (α-band) and 530 nm (Β-band). When the temperature is increased to about 278 K this non-equilibrium form of the reduced enzyme is relaxed to the corresponding equilibrium form with a single absorption band at 548 nm in the visible region characteristic for a high-spin heme iron.

Key words

Cytochrome P-450 Absorption spectra Reduction Non-equilibrium conformational states 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Blumenfeld LA, Davidov RM, Fel NS, Magonov SN, Vilu RO (1974) Studies on the conformational changes of metalloproteins induced by electrons in water-ethylene glycol solutions at low temperatures. Cytochrome C. FEBS Lett 45:256–258Google Scholar
  2. Blumenfeld LA, Davidov RM (1979) Chemical reactivity of metalloproteins in conformationally out-of-equilibrium states. Biochim Biophys Acta 549:255–280Google Scholar
  3. Champion PM, Münck E, Debrunner PG, Moss TH, Lipscomb JD, Gunsalus IC (1975) The magnetic susceptibility of reduced cytochrome P-450cam. Biochim Biophys Acta 376:579–582Google Scholar
  4. Cramer SP, Dawson JH, Hodgson KO, Hager LP (1978) Studies on the ferric forms of cytochrome P-450 and chloroperoxidase by extended X-ray absorption fine structure. J Am Chem Soc 100:7282–7290Google Scholar
  5. Dainton FS, Salmon GA, Wardman P (1969) The radiation chemistry of liquid and glassy methanol. Proc R Soc London A 313:1–30Google Scholar
  6. Gasyna Z (1979) Transient intermediates in the reduction of Fe (III) myoglobin-ligand complexes by electrons at low temperature. Biochim Biophys Acta 577:207–216Google Scholar
  7. Greschner S, Davidov RM, JÄnig G-R, Ruckpaul K, Blumenfeld LA (1979) Spectral properties of non-equilibrium states in cytochrome P-450 formed by reduction at subzero temperature. Acta Biol Med Germ 38:443–448Google Scholar
  8. Haugen DA, Coon MJ (1976) Properties of electrophoretically homogeneous phenobarbital-inducible and Β-naphtoflavone-inducible forms of liver microsomal cytochrome P-450. J Biol Chem 251:7929–7939Google Scholar
  9. Hoard JL (1975) Stereochemistry of porphyrins and metalloporphyrins. In:Smith KM (ed) Porphyrins and metalloporphyrins. Elsevier, Amsterdam New York Oxford, pp 317–380Google Scholar
  10. Imai J, Sato R (1974) A gel-electrophoretically homogenous preparation of cytochrome P-450 from liver microsomes of phenobarbital pretreated rabbits. Biochem Biophys Res Commun 60:8–14Google Scholar
  11. Ishimura Y (1978) Mechanism of cytochrome P-450 catalyzed reactions. In: Sato R, Omura T (eds) Cytochrome P-450. Kondansha-Ltd, Tokyo and Academic Press, New York London, pp 209–227Google Scholar
  12. Karuzina II, Bachmanova GI, Mengazetdinov DE, Myasoedova KN, Zhikhareva VO, Kuznetsova GP, Archakov AI (1979) Isolation and properties of cytochrome P-450 from phenobarbital-induced rabbit liver microsomes. Biokhimia USSR 44:1049–1057Google Scholar
  13. Magonov SN, Davidov RM, Blumenfeld LA, Vilu RO, Arutjunjan AM, Sharonov Ju A (1978) Absorption and magnetic circular dichroism spectra of non-equilibrium states of hemoproteins. II. Myoglobin and its complexes. Mol Biol USSR 12:1182–1190Google Scholar
  14. Ruckpaul K, Rein H, JÄnig G-R, Winkler W, Ristau O (1977) Circular dichroism of partially purified cytochrome P-450 from rabbit liver microsomes. Croat Chem Acta 49:339–346Google Scholar

Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • S. Greschner
    • 1
  1. 1.Central Institute of Molecular BiologyAcademy of Sciences of the GDRBerlin-BuchGerman Democratic Republic

Personalised recommendations