[Protein-protein interactions of cytochromes P450 3A4 and 3A5 with their intermediate redox partners cytochromes b5]

Biomed Khim. 2015 Jul-Aug;61(4):468-73. doi: 10.18097/PBMC20156104468.
[Article in Russian]

Abstract
in English, Russian

Molecular interactions between proteins redox partners (cytochromes Р450 3А4, 3А5 and cytochrome b5) within the monooxygenase system, which is known to be involved in drug biotransformation, were investigated. Human cytochromes Р450 3А4 and 3А5 (CYP3A4 and CYP3A5) form complexes with various cytochromes b5: the microsomal (b5mc) and mitochondrial (b5om) forms of this protein, as well as with 2 "chimeric" proteins, b5(om-mc), b5(mc-om). Kinetic constants and equilibrium dissociation constants were determined by the SPR biosensor. Essential distinction between CYP3A4 and CYP3A5 was only observed upon their interactions with cytochrome b5om. Electroanalytical characteristics of electrodes with immobilized hemoproteins were obtained. The electrochemical analysis of CYP3A4, CYP3A5, b5mc, b5om, b5(om-mc), and b5(mc-om) immobilized on screen printed graphite electrodes modified with membranous matrix revealed that these proteins have very close reduction potentials -0.435  -0.350 V (vs. Ag/AgCl). Cytochrome b5mc was shown to be capable of stimulating the electrocatalytic activity of CYP3A4 in the presence of its substrate testosterone.

Issledovany mezhmolekuliarnye vzaimodeĭstviia mezhdu belkami-partnerami monooksigenaznoĭ sistemy biotransformatsii lekarstvennykh preparatov: tsitokhromami R450 3A4 i R450 3A5 i tsitokhromom b5. Tsitokhromy R450 3A4 i R450 3A5 obrazuiut kompleksy s kazhdoĭ iz form tsitokhroma b5 (mikrosomal'naia i mitokhondrial'naia formy - b5mc i b5om i dve “khimernye” konstruktsii b5(om-mc), b5(mc-om)), prichem sushchestvennoe razlichie nabliudalos' tol'ko vo vzaimodeĭstvii s b5om. Opredeleny élektroanaliticheskie kharakteristiki élektrodov s immobilizovannymi gemoproteinami: tsitokhromom R450 3A4, R450 3A5, b5mc, b5om, b5(om-mc) i b5(mc-om). Élektrokhimicheskiĭ analiz pokazal, chto vse éti belki obladaiut ochen' blizkimi redoks-potentsialami -0,435  -0,350 (otn. Ag/AgCl). V to zhe vremia, nabliudalos' stimuliruiushchee vliianie tsitokhroma b5mc na élektrokataliticheskie svoĭstva tsitokhroma R450 3A4.

Keywords: SPR biosensor; cytochrome b5; cytochromes P450; electrocatalysis; electrochemistry; electron transfer; protein-protein interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biocatalysis
  • Cytochrome P-450 CYP3A / chemistry*
  • Cytochromes b5 / chemistry*
  • Electrochemical Techniques
  • Enzymes, Immobilized / chemistry
  • Humans
  • Isoenzymes / chemistry
  • Microsomes / chemistry
  • Microsomes / metabolism
  • Mitochondria / chemistry
  • Mitochondria / metabolism
  • Oxidation-Reduction
  • Protein Array Analysis
  • Protein Binding
  • Recombinant Proteins / chemistry
  • Surface Plasmon Resonance

Substances

  • Enzymes, Immobilized
  • Isoenzymes
  • Recombinant Proteins
  • Cytochromes b5
  • CYP3A5 protein, human
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human