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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
13
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pubmed:dateCreated |
1997-5-2
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pubmed:databankReference | |
pubmed:abstractText |
We report the purification, molecular cloning, and expression of a novel cytosolic calcium-independent phospholipase A2 (iPLA2) from Chinese hamster ovary cells, which lacks extended homology to other phospholipases. iPLA2 is an 85-kDa protein that exists as a multimeric complex of 270-350 kDa with a specific activity of 1 micromol/min/mg. The full-length cDNA clone encodes a 752-amino acid cytoplasmic protein with one lipase motif (GXS465XG) and eight ankyrin repeats. Expression of the cDNA in mammalian cells generates an active 85-kDa protein. Mutagenesis studies show that Ser465 and the ankyrin repeats are required for activity. We demonstrate that iPLA2 selectively hydrolyzes the sn-2 over sn-1 fatty acid by 5-fold for 1,2-dipalmitoyl phosphatidylcholine in a mixed micelle. Moreover, we found the fatty acid preference at the sn-2 position to be highly dependent upon substrate presentation. However, iPLA2 does have a marked preference for 1,2-dipalmitoyl phosphatidic acid presented in a vesicle, generating the lipid second messenger lysophosphatidic acid. Finally the enzyme is able to hydrolyze the acetyl moiety at the sn-2 position of platelet-activating factor.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Ankyrins,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Isoenzymes,
http://linkedlifedata.com/resource/pubmed/chemical/Phospholipases A,
http://linkedlifedata.com/resource/pubmed/chemical/Phospholipases A2
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
28
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pubmed:volume |
272
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
8567-75
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pubmed:dateRevised |
2007-11-15
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pubmed:meshHeading |
pubmed-meshheading:9079687-Amino Acid Sequence,
pubmed-meshheading:9079687-Animals,
pubmed-meshheading:9079687-Ankyrins,
pubmed-meshheading:9079687-CHO Cells,
pubmed-meshheading:9079687-Calcium,
pubmed-meshheading:9079687-Cloning, Molecular,
pubmed-meshheading:9079687-Cricetinae,
pubmed-meshheading:9079687-Cytosol,
pubmed-meshheading:9079687-Humans,
pubmed-meshheading:9079687-Isoenzymes,
pubmed-meshheading:9079687-Molecular Sequence Data,
pubmed-meshheading:9079687-Molecular Weight,
pubmed-meshheading:9079687-Phospholipases A,
pubmed-meshheading:9079687-Phospholipases A2,
pubmed-meshheading:9079687-Sequence Alignment
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pubmed:year |
1997
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pubmed:articleTitle |
A novel cytosolic calcium-independent phospholipase A2 contains eight ankyrin motifs.
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pubmed:affiliation |
Genetics Institute, Cambridge, Massachusetts 02140, USA.
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pubmed:publicationType |
Journal Article
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