UniProt functional annotation for P68402



	UniProt functional annotation for P68402

UniProt code: P68402.

Organism: Homo sapiens (Human).

Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.

Function: Alpha2 catalytic subunit of the cytosolic type I platelet- activating factor (PAF) acetylhydrolase (PAF-AH (I)) heterotetrameric enzyme that catalyzes the hydrolyze of the acetyl group at the sn-2 position of PAF and its analogs and modulates the action of PAF. The activity and substrate specificity of PAF-AH (I) are affected by its subunit composition. The alpha2/alpha2 homodimer (PAFAH1B2/PAFAH1B2 homodimer) hydrolyzes PAF and 1-O-alkyl-2-acetyl-sn-glycero-3- phosphorylethanolamine (AAGPE) more efficiently than 1-O-alkyl-2- acetyl-sn-glycero-3-phosphoric acid (AAGPA). In contrast, the alpha1/alpha2 heterodimer(PAFAH1B3/PAFAH1B3 heterodimer) hydrolyzes AAGPA more efficiently than PAF, but has little hydrolytic activity towards AAGPE (By similarity). May play a role in male germ cell meiosis during the late pachytenestage and meiotic divisions as well as early spermiogenesis (By similarity). {ECO:0000250|UniProtKB:P68401, ECO:0000250|UniProtKB:Q61206}.

Catalytic activity: Reaction=a 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine + H2O = 1-O- alkyl-sn-glycero-3-phosphocholine + acetate + H(+); Xref=Rhea:RHEA:17777, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:30909, ChEBI:CHEBI:36707; EC=3.1.1.47; Evidence={ECO:0000250|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:17778; Evidence={ECO:0000250|UniProtKB:P68401};

Catalytic activity: Reaction=1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine + H2O = 1- O-hexadecyl-sn-glycero-3-phosphocholine + acetate + H(+); Xref=Rhea:RHEA:40479, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:44811, ChEBI:CHEBI:64496; Evidence={ECO:0000250|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:40480; Evidence={ECO:0000250|UniProtKB:P68401};

Catalytic activity: Reaction=1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphate + H2O = 1-O- hexadecyl-sn-glycero-3-phosphate + acetate + H(+); Xref=Rhea:RHEA:41704, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:77580, ChEBI:CHEBI:78385; Evidence={ECO:0000250|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:41705; Evidence={ECO:0000250|UniProtKB:P68401};

Catalytic activity: Reaction=1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphoethanolamine + H2O = 1-O-hexadecyl-sn-glycero-3-phosphoethanolamine + acetate + H(+); Xref=Rhea:RHEA:41708, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:78387, ChEBI:CHEBI:78390; Evidence={ECO:0000250|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:41709; Evidence={ECO:0000250|UniProtKB:P68401};

Activity regulation: Beta subunit (PAFAH1B1) stimulates the acetylhydrolase activity of the alpha2/alpha2 catalytic homodimer. {ECO:0000250|UniProtKB:P68401}.

Subunit: Forms a catalytic dimer which is either homodimer (alpha2/alpha2 homodimer) or heterodimer with PAFAH1B3 (alpha2/alpha1 heterodimer). Component of the cytosolic (PAF-AH (I)) heterotetrameric enzyme, which is composed of PAFAH1B1 (beta), PAFAH1B2 (alpha2) and PAFAH1B3 (alpha1) subunits. The catalytic activity of the enzyme resides in the alpha1 (PAFAH1B3) and alpha2 (PAFAH1B2) subunits, whereas the beta subunit (PAFAH1B1) has regulatory activity. Trimer formation is not essential for the catalytic activity (By similarity). Interacts (homodimer form) with PAFAH1B1 (homodimer form); PAFAH1B2 competes with NDEL1 for PAFAH1B1 binding (PubMed:15572112). Interacts with VLDLR; this interaction may modulate the Reelin pathway (By similarity). {ECO:0000250|UniProtKB:P68401, ECO:0000250|UniProtKB:Q61206, ECO:0000269|PubMed:15572112}.

Subcellular location: Cytoplasm.

Tissue specificity: Ubiquitous. {ECO:0000269|PubMed:9144386}.

Miscellaneous: Originally the subunits of the type I platelet- activating factor (PAF) acetylhydrolase was named alpha (PAFAH1B1), beta (PAFAH1B2) and gamma (PAFAH1B3) (PubMed:9144386) (By similarity). Now these subunits have been renamed beta (PAFAH1B1), alpha2 (PAFAH1B2) and alpha1 (PAFAH1B3) respectively (By similarity). {ECO:0000250|UniProtKB:P43034, ECO:0000250|UniProtKB:Q15102, ECO:0000250|UniProtKB:Q29460, ECO:0000303|PubMed:9144386}.

Similarity: Belongs to the 'GDSL' lipolytic enzyme family. Platelet- activating factor acetylhydrolase IB beta/gamma subunits subfamily. {ECO:0000305}.

Annotations taken from UniProtKB at the EBI.


Organism:		Homo sapiens (Human).
Taxonomy:		Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.



Function:		Alpha2 catalytic subunit of the cytosolic type I platelet- activating factor (PAF) acetylhydrolase (PAF-AH (I)) heterotetrameric enzyme that catalyzes the hydrolyze of the acetyl group at the sn-2 position of PAF and its analogs and modulates the action of PAF. The activity and substrate specificity of PAF-AH (I) are affected by its subunit composition. The alpha2/alpha2 homodimer (PAFAH1B2/PAFAH1B2 homodimer) hydrolyzes PAF and 1-O-alkyl-2-acetyl-sn-glycero-3- phosphorylethanolamine (AAGPE) more efficiently than 1-O-alkyl-2- acetyl-sn-glycero-3-phosphoric acid (AAGPA). In contrast, the alpha1/alpha2 heterodimer(PAFAH1B3/PAFAH1B3 heterodimer) hydrolyzes AAGPA more efficiently than PAF, but has little hydrolytic activity towards AAGPE (By similarity). May play a role in male germ cell meiosis during the late pachytenestage and meiotic divisions as well as early spermiogenesis (By similarity). {ECO:0000250\|UniProtKB:P68401, ECO:0000250\|UniProtKB:Q61206}.


Catalytic activity:		Reaction=a 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine + H2O = 1-O- alkyl-sn-glycero-3-phosphocholine + acetate + H(+); Xref=Rhea:RHEA:17777, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:30909, ChEBI:CHEBI:36707; EC=3.1.1.47; Evidence={ECO:0000250\|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:17778; Evidence={ECO:0000250\|UniProtKB:P68401};
Catalytic activity:		Reaction=1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine + H2O = 1- O-hexadecyl-sn-glycero-3-phosphocholine + acetate + H(+); Xref=Rhea:RHEA:40479, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:44811, ChEBI:CHEBI:64496; Evidence={ECO:0000250\|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:40480; Evidence={ECO:0000250\|UniProtKB:P68401};
Catalytic activity:		Reaction=1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphate + H2O = 1-O- hexadecyl-sn-glycero-3-phosphate + acetate + H(+); Xref=Rhea:RHEA:41704, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:77580, ChEBI:CHEBI:78385; Evidence={ECO:0000250\|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:41705; Evidence={ECO:0000250\|UniProtKB:P68401};
Catalytic activity:		Reaction=1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphoethanolamine + H2O = 1-O-hexadecyl-sn-glycero-3-phosphoethanolamine + acetate + H(+); Xref=Rhea:RHEA:41708, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30089, ChEBI:CHEBI:78387, ChEBI:CHEBI:78390; Evidence={ECO:0000250\|UniProtKB:P68401}; PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:41709; Evidence={ECO:0000250\|UniProtKB:P68401};
Activity regulation:		Beta subunit (PAFAH1B1) stimulates the acetylhydrolase activity of the alpha2/alpha2 catalytic homodimer. {ECO:0000250\|UniProtKB:P68401}.
Subunit:		Forms a catalytic dimer which is either homodimer (alpha2/alpha2 homodimer) or heterodimer with PAFAH1B3 (alpha2/alpha1 heterodimer). Component of the cytosolic (PAF-AH (I)) heterotetrameric enzyme, which is composed of PAFAH1B1 (beta), PAFAH1B2 (alpha2) and PAFAH1B3 (alpha1) subunits. The catalytic activity of the enzyme resides in the alpha1 (PAFAH1B3) and alpha2 (PAFAH1B2) subunits, whereas the beta subunit (PAFAH1B1) has regulatory activity. Trimer formation is not essential for the catalytic activity (By similarity). Interacts (homodimer form) with PAFAH1B1 (homodimer form); PAFAH1B2 competes with NDEL1 for PAFAH1B1 binding (PubMed:15572112). Interacts with VLDLR; this interaction may modulate the Reelin pathway (By similarity). {ECO:0000250\|UniProtKB:P68401, ECO:0000250\|UniProtKB:Q61206, ECO:0000269\|PubMed:15572112}.
Subcellular location:		Cytoplasm.
Tissue specificity:		Ubiquitous. {ECO:0000269\|PubMed:9144386}.
Miscellaneous:		Originally the subunits of the type I platelet- activating factor (PAF) acetylhydrolase was named alpha (PAFAH1B1), beta (PAFAH1B2) and gamma (PAFAH1B3) (PubMed:9144386) (By similarity). Now these subunits have been renamed beta (PAFAH1B1), alpha2 (PAFAH1B2) and alpha1 (PAFAH1B3) respectively (By similarity). {ECO:0000250\|UniProtKB:P43034, ECO:0000250\|UniProtKB:Q15102, ECO:0000250\|UniProtKB:Q29460, ECO:0000303\|PubMed:9144386}.
Similarity:		Belongs to the 'GDSL' lipolytic enzyme family. Platelet- activating factor acetylhydrolase IB beta/gamma subunits subfamily. {ECO:0000305}.