Relationships between paraoxon and 2-coumaranone hydrolytic activities in sera genotyped for PON1 Q192R polymorphism.
OBJECTIVE
To set-up a method for a direct evaluation in human serum of paraoxonase enzymatic activities, establishing a possible correlation with Q192R genotype polymorphism.


METHODS
101 different human serum samples were genotyped for paraoxonase Q192R polymorphism by PCR restriction analysis, and evaluated spectrophotometrically with regard to paraoxon and 2-coumaranone hydrolytic activities. Both activities of paraoxonase were assayed, quantified through normalization by arylesterase activity, and compared with the data concerning Q/R genetic polymorphism.


RESULTS
The mean normalized paraoxonase activity was found to be significantly higher in RR than in QQ human sera (3.99+/-0.6 versus 1.32+/-0.44; P<0.0001); instead, the 2-coumaranone hydrolysis showed an opposite trend (0.10+/-0.02 versus 0.23+/-0.04, in RR and QQ sera respectively; P<0.0001).


CONCLUSIONS
These methods were successfully applied to the whole serum, suggesting a possible use of this approach for a clinically relevant phenotypic characterization.
Giacominelli-Stuffler
Roberto
R
Department of Biomedical Sciences, University of Teramo, Teramo, Italy.
Angelucci
Clotilde Beatrice
CB
Liberatoscioli
Laura
L
Cortese
Claudio
C
Dainese
Enrico
E
Maccarrone
Mauro
M
D000328:Adult; D043303:Aryldialkylphosphatase / Q000378:metabolism*; D001572:Benzofurans / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000378:metabolism*; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D010261:Paraoxon / Q000378:metabolism*; D011110:Polymorphism, Genetic; D013379:Substrate Specificity
D001572:Benzofurans; D002800:Cholinesterase Inhibitors; C545827:2-coumaranone; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human; D010261:Paraoxon