Integrative analytical approach by capillary electrophoresis and kinetics under high pressure optimized for deciphering intrinsic and extrinsic cofactors that modulate activity and stability of human paraoxonase (PON1).
Paraoxonase (PON1) is working in vivo in a particular dynamic environment including HDL particles and associated molecules. To decipher the respective and/or concomitant role of the different cofactors involved in this molecular organization, an approach using multiple experimental techniques based on capillary electrophoresis and classical kinetics or kinetics under high pressure was implemented. The effects of calcium and phosphate as protein or plasma cofactor, of human phosphate binding protein (HPBP) as enzyme chaperone, and of a PON1 inhibitor as an active site stabilizer, on the catalytic activities and functional oligomerization of PON1 were scrutinized. PON1 displays two distinct catalytic behaviors, one against esters and lactones, the other against organophosphorus compounds; its functional states and catalytic activities against these substrates are differently modulated by the molecular environment; PON1 exists under several active multimeric forms; the binding of HPBP amends the size of the oligomeric states and exerts a stabilizing effect on the activities of PON1; PON1 functional properties are modulated by HPBP, calcium and phosphate. This integrative approach using several optimized analytical techniques allowed performing comparison of catalytic properties and oligomeric states of functional PON1 in different enzyme preparations. Relevance of these data to understand in vivo physiological PON1 functioning is mandatory.
Renault
Frédérique
F
Département de Toxicologie, Institut de Recherche Biomédicale des Armées, Antenne La Tronche-CRSSA, BP 87, 38702 La Tronche cedex, France.
Carus
Tiffany
T
Cléry-Barraud
Cécile
C
Elias
Mikael
M
Chabrière
Eric
E
Masson
Patrick
P
Rochu
Daniel
D
D043303:Aryldialkylphosphatase / Q000737:chemistry* / Q000378:metabolism*; D001274:Atmospheric Pressure; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D003067:Coenzymes / Q000737:chemistry* / Q000378:metabolism*; D019075:Electrophoresis, Capillary / Q000379:methods*; D004795:Enzyme Stability; D006801:Humans; D006912:Hydroxyquinolines / Q000494:pharmacology; D007700:Kinetics; D008958:Models, Molecular; D028044:Phosphate-Binding Proteins / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism; D055503:Protein Multimerization; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D003067:Coenzymes; D006912:Hydroxyquinolines; D028044:Phosphate-Binding Proteins; D010710:Phosphates; D011994:Recombinant Proteins; C107724:2-hydroxyquinoline; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human; D002118:Calcium