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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1984-1-27
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pubmed:abstractText |
A novel fluorescent phospholipid analogue, 1-triacontanoyl-2-(pyren-1-yl)hexanoyl-sn-glycero-3-phosphocholine (C30PHPC) was employed as a substrate for human pancreatic phospholipase A2. C30PHPC has a main endothermic phase transition with Tm at 46 degrees C as determined by differential scanning calorimetry (DSC). For an aqueous dispersion of C30PHPC the ratio of the intensities of pyrene excimer and monomer fluorescence emission, (IE/IM) has a maximum between 32 and 36 degrees C. The excimer emission intensity (at 480 nm) exceeds the monomer emission intensity (at 400 nm) 6.5-fold thus indicating a close packing of the phospholipid pyrene moieties in the lipid phase. C30PHPC has a limiting mean molecular area of 37 A2 at surface pressure 35 dyn cm-1 as judged by the compression isotherm at an air-water interphase. The hydrolysis of C30PHPC by human pancreatic phospholipase A2 was followed by monitoring the increase in the pyrene monomer fluorescence emission intensity occurring as a consequence of transfer of the reaction product, pyren-1-yl hexanoic acid into the aqueous phase. The enzyme reaction exhibited an apparent Km of 2.0 microM substrate. Calcium at a concentration of 0.2 mM activated the enzyme 4-fold. Maximal hydrolytic rates were obtained at 45 degrees C and at pH between 5.5 and 6.5. The enzyme reaction could be inhibited by 5 mM EDTA, confirming the absolute requirement for Ca2+ of this enzyme. The present fluorimetric assay easily detects hydrolysis of C30PHPC in the pmol min-1 range. Accordingly, less than nanogram levels of human pancreatic phospholipase A2 can be detected.
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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/Fluorescent Dyes,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphatidylcholines,
http://linkedlifedata.com/resource/pubmed/chemical/Phospholipases,
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 |
Sep
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pubmed:issn |
0009-3084
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
33
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
283-92
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pubmed:dateRevised |
2007-11-15
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pubmed:meshHeading |
pubmed-meshheading:6640814-Fluorescent Dyes,
pubmed-meshheading:6640814-Humans,
pubmed-meshheading:6640814-Hydrolysis,
pubmed-meshheading:6640814-Kinetics,
pubmed-meshheading:6640814-Models, Molecular,
pubmed-meshheading:6640814-Molecular Conformation,
pubmed-meshheading:6640814-Pancreas,
pubmed-meshheading:6640814-Phosphatidylcholines,
pubmed-meshheading:6640814-Phospholipases,
pubmed-meshheading:6640814-Phospholipases A,
pubmed-meshheading:6640814-Phospholipases A2,
pubmed-meshheading:6640814-Spectrometry, Fluorescence
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pubmed:year |
1983
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pubmed:articleTitle |
Hydrolysis of 1-triacontanoyl-2-(pyren-1-yl)hexanoyl-sn-glycero-3-phosphocholine by human pancreatic phospholipase A2.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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