pregnancy zone protein; C3 & PZP-like alpha-2-macroglobulin domain-containing protein 6 (PZP, CPAMD6)

Function: - able to inhibit all four classes of proteinases by a unique 'trapping' mechanism - PZP has a peptide stretch, called the 'bait region' which contains specific cleavage sites for different proteinases (as does alpha-2 macroglobulin) - when a proteinase cleaves the bait region, a conformational change is induced in PZP which traps the proteinase - the entrapped enzyme remains active against low molecular weight substrates (activity against high molecular weight substrates is greatly reduced) - following cleavage in the bait region, a thioester bond is hydrolyzed & mediates the covalent binding of the protein to the proteinase Structure: - homotetramer, which consists of two pairs of disulfide-linked chains - belongs to the protease inhibitor I39 (alpha-2-macroglobulin) family Compartment: secreted Alternative splicing: named isoforms=2 Expression: - plasma - prominent constituent of late-pregnancy sera

General

glycoprotein protease inhibitor secreted protein

Properties

SIZE: entity length = 1482 aa MW = 164 kD COMPARTMENT: extracellular compartment MOTIF: signal sequence {1-25} MOTIF: N-glycosylation site {N24} N-glycosylation site {N54} N-glycosylation site {N69} N-glycosylation site {N246} N-glycosylation site {N392} N-glycosylation site {N406} Bait region {685-735} N-glycosylation site {N753} N-glycosylation site {N875} N-glycosylation site {N932} N-glycosylation site {N997} N-glycosylation site {N1430} INHIBITS: protease

Database Correlations

OMIM 176420 UniProt P20742 PFAM correlations

References

UniProt :accession P20742