Abstract
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.
Similar content being viewed by others
References
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 45:256–258
Blumenfeld LA, Davidov RM (1979) Chemical reactivity of metalloproteins in conformationally out-of-equilibrium states. Biochim Biophys Acta 549:255–280
Champion PM, Münck E, Debrunner PG, Moss TH, Lipscomb JD, Gunsalus IC (1975) The magnetic susceptibility of reduced cytochrome P-450cam. Biochim Biophys Acta 376:579–582
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 100:7282–7290
Dainton FS, Salmon GA, Wardman P (1969) The radiation chemistry of liquid and glassy methanol. Proc R Soc London A 313:1–30
Gasyna Z (1979) Transient intermediates in the reduction of Fe (III) myoglobin-ligand complexes by electrons at low temperature. Biochim Biophys Acta 577:207–216
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 38:443–448
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 251:7929–7939
Hoard JL (1975) Stereochemistry of porphyrins and metalloporphyrins. In:Smith KM (ed) Porphyrins and metalloporphyrins. Elsevier, Amsterdam New York Oxford, pp 317–380
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 60:8–14
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 209–227
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 44:1049–1057
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 12:1182–1190
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 49:339–346
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Greschner, S. Absorption spectra of highly purified liver microsomal cytochrome P-450 in non-equilibrium conformational states at low temperatures. Biophys. Struct. Mechanism 9, 29–34 (1982). https://doi.org/10.1007/BF00536013
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00536013