Paraoxonase 1 (PON1) ELISA Kit for Human

The enzyme encoded by this gene is an arylesterase that mainly hydrolyzes paroxon to produce p-nitrophenol. Paroxon is an organophosphorus anticholinesterase compound that is produced in vivo by oxidation of the insecticide parathion. Polymorphisms in this gene are a risk factor in coronary artery disease. The gene is found in a cluster of three related paraoxonase genes at 7q21.3. [provided by RefSeq, Oct 2008]

Function: Hydrolyzes the toxic metabolites of a variety of organophosphorus insecticides. Capable of hydrolyzing a broad spectrum of organophosphate substrates and lactones, and a number of aromatic carboxylic acid esters. Mediates an enzymatic protection of low density lipoproteins against oxidative modification and the consequent series of events leading to atheroma formation. Ref.18 Ref.20

Catalytic activity: A phenyl acetate + H2O = a phenol + acetate. Ref.3 Ref.15 Ref.16 Ref.20 Ref.24An aryl dialkyl phosphate + H2O = dialkyl phosphate + an aryl alcohol. Ref.3 Ref.15 Ref.16 Ref.20 Ref.24An N-acyl-L-homoserine lactone + H2O = an N-acyl-L-homoserine. Ref.3 Ref.15 Ref.16 Ref.20 Ref.24

Cofactor: Binds 2 calcium ions per subunit.

Subunit structure: Homodimer. Heterooligomer with phosphate-binding protein (HPBP). Interacts with CLU. Ref.14 Ref.20 Ref.22

Subcellular location: Secreted › extracellular space.

Tissue specificity: Plasma, associated with HDL (at protein level). Expressed in liver, but not in heart, brain, placenta, lung, skeletal muscle, kidney or pancreas. Ref.13 Ref.14

Post-translational modification: Glycosylated.The signal sequence is not cleaved.Present in two forms, form B contains a disulfide bond, form A does not.

Polymorphism: The allelic form of the enzyme with Gln-192 (allozyme A) hydrolyzes paraoxon with a low turnover number and the one with Arg-192 (allozyme B) with a high turnover number.

Involvement in disease: Microvascular complications of diabetes 5 (MVCD5) [MIM:612633]: Pathological conditions that develop in numerous tissues and organs as a consequence of diabetes mellitus. They include diabetic retinopathy, diabetic nephropathy leading to end-stage renal disease, and diabetic neuropathy. Diabetic retinopathy remains the major cause of new-onset blindness among diabetic adults. It is characterized by vascular permeability and increased tissue ischemia and angiogenesis.Note: Disease susceptibility is associated with variations affecting the gene represented in this entry. Homozygosity for the Leu-55 allele is strongly associated with the development of retinal disease in diabetic patients.

Miscellaneous: The preferential association of PON1 with HDL is mediated in part by its signal peptide, by binding phospholipids directly, rather than binding apo AI. The retained signal peptide may allow transfer of the protein between phospholipid surfaces.

Sequence similarities: Belongs to the paraoxonase family.