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paraoxonase/arylesterase 1; serum aryldiakylphosphatase 1; A-esterase 1; aromatic esterase 1 (PON1 PON)

Function: - hydrolyzes paroxon - hydrolyzes the toxic metabolites of a variety of organophosphorus insecticides - capable of hydrolyzing a broad spectrum of organophosphate substrates & a number of aromatic carboxylic acid esters - may mediate enzymatic protection of low density lipoproteins against oxidative modification & the consequent series of events leading to atheroma formation - heterooligomer with phosphate-binding protein (HPBP) - association of PON1 with HDL is mediated in part by its signal peptide, by binding phospholipids directly, rather than binding apo A1 - the retained signal peptide may allow transfer of the protein between phospholipid surfaces [2] a phenyl acetate + H2O a phenol + acetate an aryl dialkyl phosphate + H2O dialkyl phosphate + an aryl alcohol Cofactor: Ca+2 - binds 2 Ca+2 per subunit Structure: - glycosylated - signal sequence is not cleaved a) preferential association of PON1 with HDL is mediated, in part, by its signal peptide, by binding phospholipids directly, rather than binding apo AI b) retained signal peptide may allow transfer of protein between phospholipid surfaces - belongs to the paraoxonase family Compartment: secreted, extracellular space Expression: plasma, associated with HDL Polymorphism: - allozyme A, allelic form with Gln-192 hydrolyzes paraoxon with low turnover number & - allozyme B, allelic form with Arg-192 hydrolyzes paraoxon with a high turnover number Pathology: - PON1 gene mutations are associated with microvascular complications of diabetes mellitus Laboratory: - PON1 gene mutation - PON1 in serum

General

Ca+2 binding protein paraoxonase, arylesterase or esterase-A

Properties

SIZE: entity length = 355 aa MW = 40 kD COMPARTMENT: plasma MOTIF: cysteine residue {C42} MODIFICATION: cysteine residue {C353} Ca+2-binding site SITE: 53-53 Ca+2-binding site SITE: 54-54 histidine residue {H115} Ca+2-binding site SITE: 117-117 Ca+2-binding site SITE: 168-168 Ca+2-binding site SITE: 169-169 Ca+2-binding site SITE: 224-224 N-glycosylation site {N227} N-glycosylation site {N253} Ca+2-binding site SITE: 269-269 Ca+2-binding site SITE: 270-270 MOTIF: N-glycosylation site {N270} N-glycosylation site {N324} cysteine residue {C353} MODIFICATION: cysteine residue {C42}

Database Correlations

OMIM 168820 UniProt P27169 KEGG correlations ENZYME correlations

References

  1. SHMPD, The Singapore human mutation & polymorphism database http://shmpd.bii.a-star.edu.sg/gene.php?genestart=A&genename=PON1
  2. UniProt :accession P27169
  3. OMIM :accession 168820