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| Enzyme Name | | Swiss-prot | KEGG |
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| Q29460 |
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| Protein name | Platelet-activating factor acetylhydrolase IB subunit gamma | 1-alkyl-2-acetylglycerophosphocholine esterase1-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetylhydrolasealkylacetyl-GPC:acetylhydrolase |
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| Synonyms | EC 3.1.1.47PAF acetylhydrolase 29 kDa subunitPAF-AH 29 kDa subunitPAF-AH subunit gammaPAFAH subunit gamma |
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| KEGG pathways | | MAP code | Pathways |
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| MAP00565 | Ether lipid metabolism |
| Swiss-prot:Accession Number | Q29460 |
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| Entry name | PA1B3_BOVIN |
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| Activity | 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine + H(2)O = 1-alkyl-sn-glycero-3-phosphocholine + acetate. |
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| Subunit | Cytosolic PAF-AH IB is formed of three subunits of 45 kDa (alpha), 30 kDa (beta) and 29 kDa (gamma). The catalytic activity of the enzyme resides in the beta and gamma subunits, whereas the alpha subunit has regulatory activity. Trimer formation is not essential for the catalytic activity. |
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| Subcellular location | Cytoplasm. |
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| Cofactor |
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| Substrates | Products |
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| KEGG-id | C04598 | C00001 | C04317 | C00033 |
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| Compound | 1-Alkyl-2-acetyl-sn-glycero-3-phosphocholine | H2O | 1-Alkyl-sn-glycerol-3-phosphocholine | Acetate |
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| Type | amine group,carbohydrate,lipid,phosphate group/phosphate ion | H2O | amine group,carbohydrate,lipid,phosphate group/phosphate ion | carboxyl group |
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| 1bwpA |  | Unbound |
| Unbound | Unbound |
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| 1bwqA | | Unbound |
| Unbound | Unbound |
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| 1bwrA | | Unbound |
| Unbound | Unbound |
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| 1es9A | | Unbound |
| Unbound | Unbound |
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| 1wabA | | Unbound |
| Unbound | Bound:ACT |
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| References for Catalytic Mechanism | | References | Sections | No. of steps in catalysis |
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| [1] | p.90-92. |
| | [2] | p.698-699 |
| | [4] | p.869-870 |
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| references | | [1] |
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| Comments | X-ray crystallography (1.7 Angstroms) |
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| PubMed ID | 8985254 |
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| Journal | Nature |
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| Year | 1997 |
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| Volume | 385 |
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| Pages | 89-93 |
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| Authors | Ho YS, Swenson L, Derewenda U, Serre L, Wei Y, Dauter Z, Hattori M, Adachi T, Aoki J, Arai H, Inoue K, Derewenda ZS |
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| Title | Brain acetylhydrolase that inactivates platelet-activating factor is a G-protein-like trimer. |
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| Related PDB | 1wab |
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| [2] |
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| Comments | X-ray crystallography (1.7 Angstroms) |
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| PubMed ID | 10469831 |
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| Journal | Protein Eng |
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| Year | 1999 |
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| Volume | 12 |
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| Pages | 693-700 |
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| Authors | Ho YS, Sheffield PJ, Masuyama J, Arai H, Li J, Aoki J, Inoue K, Derewenda U, Derewenda ZS |
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| Title | Probing the substrate specificity of the intracellular brain platelet-activating factor acetylhydrolase. |
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| Related PDB | 1bwp,1bwq,1bwr |
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| [3] |
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| PubMed ID | 11080681 |
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| Journal | Biochim Biophys Acta |
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| Year | 2000 |
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| Volume | 1488 |
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| Pages | 102-23 |
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| Authors | Tjoelker LW, Stafforini DM |
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| Title | Platelet-activating factor acetylhydrolases in health and disease. |
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| [4] |
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| Comments | functional consequences of the dimerization |
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| PubMed ID | 11239086 |
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| Journal | Protein Eng |
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| Year | 2000 |
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| Volume | 13 |
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| Pages | 865-71 |
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| Authors | McMullen TW, Li J, Sheffield PJ, Aoki J, Martin TW, Arai H, Inoue K, Derewenda ZS |
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| Title | The functional implications of the dimerization of the catalytic subunits of the mammalian brain platelet-activating factor acetylhydrolase (Ib). |
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| Related PDB | 1es9 |
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| [5] |
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| Comments | X-ray crystallography (2.1 Angstroms) |
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| PubMed ID | 11522926 |
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| Journal | Protein Eng |
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| Year | 2001 |
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| Volume | 14 |
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| Pages | 513-9 |
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| Authors | Sheffield PJ, McMullen TW, Li J, Ho YS, Garrard SM, Derewenda U, Derewenda ZS |
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| Title | Preparation and crystal structure of the recombinant alpha(1)/alpha(2) catalytic heterodimer of bovine brain platelet-activating factor acetylhydrolase Ib. |
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| comments | The paper [1] on the crystal structure of this enzyme reported that it has a trypsin-like catalytic triad of Ser47, His195 and Asp 192, as well as an oxyanion hole. Moreover, Ser47 has been identified as the putative nucleohile, whereas the oxyanion hole seems to be composed of mainchain amide groups of Ser47 and Gly74 along with sidechain amide of Asn104, according to this paper [1].
The paper [4] suggested that this enzyme has got another unique feature in the active site. Arg29 and Arg22 in one chain contribute to the catalytic site of the other monomer across the dimer interface. Thus, the dimerization is essential for both stability and catalytic activity of this enzyme [4].
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| created | updated |
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| 2002-07-04 | 2010-11-30 |
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