Paraoxonase

paraoxonase 1
Identifiers
Symbol	PON1
Alt. symbols	PON
Entrez	5444
HUGO	9204
OMIM	168820
RefSeq	NM_000446
UniProt	P27169
Other data
EC number	3.1.8.1
Locus	Chr. 7 q21.3

paraoxonase 2
Identifiers
Symbol	PON2
Entrez	5445
HUGO	9205
OMIM	602447
RefSeq	NM_000305
UniProt	Q15165
Other data
EC number	3.1.8.1
Locus	Chr. 7 q21.3

paraoxonase 3
Identifiers
Symbol	PON3
Entrez	5446
HUGO	9206
OMIM	602720
RefSeq	NM_000940
UniProt	Q15166
Other data
EC number	3.1.8.1
Locus	Chr. 7 q21.3

Paraoxonases are a group of enzymes involved in the hydrolysis of organophosphates.^[1]

Contents 1 History 2 Types 3 Clinical Significance 4 External links 5 References

History

PON was identified as an enzyme having organophosphates as its substrates. Reports of the geographic differences in population frequencies of paraoxonase activity and genetic analysis led to uncovering the genetic polymorphism.

Types

There are 3 known genotypic forms of paraoxonases. They are coded for by the PON set of genes – PON1, PON2 and PON3 – located on the long arm of chromosome 7.^[2] The differences between them lie in their location and activity.

• PON1 is synthesized in the liver and transported along with HDL in the plasma. It functions as an antioxidant; it prevents the oxidation of LDL. Its serum concentration is influenced by inflammatory changes and the levels of serum oxidised-LDL.

• PON2 is a ubiquitously expressed intracellular protein that can protect cells against oxidative damage.^[3]

• PON3 is similar to PON1 in activity but differs from it in substrate specificity. Additionally, it is not regulated by inflammation and levels of oxidised lipids.^[4]

Clinical Significance

PON1 and PON3 are implicated in lowering the risk of developing coronary artery disease and atherosclerosis. PON1 and PON3 prevent the formation of atherogenic oxidised-LDL, the form of LDL present in foam cells of an atheromatous plaque.

External links

• Proteopedia 1v04

References