Protein Domain : IPR002640

Type:  Family Name:  Arylesterase
Description:  The serum paraoxonases/arylesterases are enzymes that catalyse the hydrolysis of the toxic metabolites of a variety of organophosphorus insecticides. Theenzymes hydrolyse a broad spectrum of organophosphate substrates, including paraoxon and a number of aromatic carboxylic acid esters (e.g., phenylacetate), and hence confer resistance to organophosphate toxicity []. Mammals have 3 distinct paraoxonase types, termed PON1-3 [, ]. In mice andhumans, the PON genes are found on the same chromosome in close proximity. PON activity has been found in variety of tissues, with highest levels in liver and serum - the source of serum PON is thought to be the liver. Unlike mammals, fish and avian species lack paraoxonase activity. Human and rabbit PONs appear to have two distinct Ca2+ binding sites, one required for stability and one required for catalytic activity. The Ca2+dependency of PONs suggests a mechanism of hydrolysis where Ca2+ acts as the electrophillic catalyst, like that proposed for phospholipase A2. Theparaoxonase enzymes, PON1 and PON3, are high density lipoprotein (HDL)- associated proteins capable of preventing oxidative modification of lowdensity lipoproteins (LPL) []. Although PON2 has oxidative properties, theenzyme does not associate with HDL. Within a given species, PON1, PON2 and PON3 share ~60% amino acid sequence identity, whereas between mammalian species particular PONs (1,2 or 3) share79-90% identity at the amino acid level. Human PON1 and PON3 share numerous conserved phosphorylation and N-glycosylation sites; however, it is not known whether the PON proteins are modified at these sites, or whether modification at these sites is required for activity in vivo []. This family consists of arylesterases (Also known as serum paraoxonase) . These enzymes hydrolyse organophosphorus esters such as paraoxon and are found in the liver and blood. They confer resistance to organophosphate toxicity []. Human arylesterase (PON1) is associated with HDL and may protect against LDL oxidation []. Short Name:  Arylesterase
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2 Child Features

DB identifier Type Name
IPR008363 Family Paraoxonase1
IPR008364 Family Paraoxonase2

1 Contains

DB identifier Type Name
IPR011042 Domain Six-bladed beta-propeller, TolB-like

2 Cross Referencess

Identifier
PF01731
PR01785

0 Found In

1 GO Annotation

GO Term Gene Name
GO:0004064 IPR002640

1 Ontology Annotations

GO Term Gene Name
GO:0004064 IPR002640

0 Parent Features

3 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
Ceric.22G016100.6.p PAC:50614530 Ceratopteris richardii 218  
Ceric.22G016200.3.p PAC:50613940 Ceratopteris richardii 269  
Ceric.22G016200.4.p PAC:50613939 Ceratopteris richardii 269  

3 Publications

First Author Title Year Journal Volume Pages PubMed ID
            9032442
            8661009
            11038162