Conference paper

Differentiation Between Type I and Type II Substrate Binding to Cytochrome P450 by Temperature Studies

G.-R. Janig ; Department of Biocatalysis and Department of Methods and Theory, Central Institute of Molecular Biology, Academy of Sciences of the GDR, 1115 Berlin-Buch, GDR
R. Misselwitz ; Department of Biocatalysis and Department of Methods and Theory, Central Institute of Molecular Biology, Academy of Sciences of the GDR, 1115 Berlin-Buch, GDR
D. Zirwer ; Department of Biocatalysis and Department of Methods and Theory, Central Institute of Molecular Biology, Academy of Sciences of the GDR, 1115 Berlin-Buch, GDR
E. Buder ; Department of Biocatalysis and Department of Methods and Theory, Central Institute of Molecular Biology, Academy of Sciences of the GDR, 1115 Berlin-Buch, GDR
H. Rein ; Department of Biocatalysis and Department of Methods and Theory, Central Institute of Molecular Biology, Academy of Sciences of the GDR, 1115 Berlin-Buch, GDR
K. Ruckpaul ; Department of Biocatalysis and Department of Methods and Theory, Central Institute of Molecular Biology, Academy of Sciences of the GDR, 1115 Berlin-Buch, GDR

Abstract

The binding reactions of type J and type II substances to
cytochrome P450 solubilized from phenobarbital induced rat liver
microsomes show different dependence on temperature. With increasing
temperature the type II binding is lowered whereas the
stability of type I substrate complexes increases. The binding enthalpies
were calculated from the van't Hoff plots and discussed
in connection with the entropy and Gibbs energy of substrate
binding to cytochrome P450. Our data on temperature dependence
provide further evidence pointing to a difference between the
binding sites of the two classes of substrates, and support the view
that the type I binding site is located in a hydrophobic part of the
cytochrome P450 molecule.

Keywords

Hrčak ID:

196365

URI

https://hrcak.srce.hr/196365

Publication date:

30.3.1977.

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