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rdf:type |
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lifeskim:mentions |
umls-concept:C0008286,
umls-concept:C0085862,
umls-concept:C0146951,
umls-concept:C0851827,
umls-concept:C1280500,
umls-concept:C1299583,
umls-concept:C1549571,
umls-concept:C1608386,
umls-concept:C1701901,
umls-concept:C1882727,
umls-concept:C2263450,
umls-concept:C2346927
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pubmed:issue |
2
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pubmed:dateCreated |
1989-10-12
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pubmed:abstractText |
Lung contains both Mg2+-dependent and Mg2+-independent phosphatidate phosphohydrolase activities. Addition of Triton X-100 (0.5%) or chlorpromazine (1 mM) leads to a marked increase in the total phosphatidate phosphohydrolase activity in rat lung microsomes (microsomal fractions), but a decrease in the Mg2+-dependent activity. These observations suggest that the Mg2+-independent activity is stimulated, whereas the Mg2+-dependent activity is inhibited. However, the possibility exists that Triton X-100 could stimulate the Mg2+-dependent enzymic activity in an Mg2+-independent manner. In addition, the positively charged amphiphilic drug could be replacing the enzyme's requirement for Mg2+. These two possibilities were examined by using subcellular fractions in which the Mg2+-dependent phosphatidate phosphohydrolase had been abolished by heat treatment at 55 degrees C for 15 min. Heat treatment does not affect the microsomal Mg2+-independent phosphohydrolase to any great extent. Since the 6-8-fold stimulations due to Triton X-100 and chlorpromazine are retained after heat treatment of this fraction, the Mg2+-independent activity must be involved. Addition of Triton X-100 and chlorpromazine to cytosol virtually abolishes the Mg2+-dependent phosphatidate phosphohydrolase activity and decreases the Mg2+-independent activity by half. Heat treatment also abolishes the Mg2+-dependent activity and decreases the Mg2+-independent activity by over half. The Mg2+-independent phosphatidate phosphohydrolase activity remaining after heat treatment was not affected by Triton X-100 or chlorpromazine. These studies demonstrate that Triton X-100 and chlorpromazine specifically stimulate the heat-stable Mg2+-independent phosphatidate phosphohydrolase activity in rat lung microsomes. In contrast, the heat-labile Mg2+-independent phosphatidate phosphohydrolase activities in cytosol are inhibited by these reagents. Triton X-100 and chlorpromazine inhibit the Mg2+-dependent phosphatidate phosphohydrolase activities in both rat lung microsomes and cytosol. These results are consistent with the view that a single Mg2+-dependent phosphatidate phosphohydrolase present in both microsomes and cytosol is specifically involved in glycerolipid metabolism.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-192211,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-197950,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-200224,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-207801,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-212108,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-212308,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-213119,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-2822021,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-3002481,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-3004406,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-3006539,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-3030367,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-3663689,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-4284297,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-4284968,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-4354154,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-4376999,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6091551,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6095917,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6100459,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6159920,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6180740,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6250446,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6257299,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6264964,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6271366,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6277611,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6277612,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6297605,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6308017,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6324013,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-64,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6824716,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-6928679,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2549979-7410548
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
261
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
673-8
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:2549979-Animals,
pubmed-meshheading:2549979-Chlorpromazine,
pubmed-meshheading:2549979-Cytosol,
pubmed-meshheading:2549979-Enzyme Activation,
pubmed-meshheading:2549979-Hot Temperature,
pubmed-meshheading:2549979-Lung,
pubmed-meshheading:2549979-Magnesium,
pubmed-meshheading:2549979-Microsomes,
pubmed-meshheading:2549979-Octoxynol,
pubmed-meshheading:2549979-Phosphatidate Phosphatase,
pubmed-meshheading:2549979-Phosphoric Monoester Hydrolases,
pubmed-meshheading:2549979-Polyethylene Glycols,
pubmed-meshheading:2549979-Rats,
pubmed-meshheading:2549979-Rats, Inbred Strains
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pubmed:year |
1989
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pubmed:articleTitle |
The effects of Triton X-100 and chlorpromazine on the Mg2+-dependent and Mg2+-independent phosphatidate phosphohydrolase activities of rat lung.
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pubmed:affiliation |
Department of Biochemistry, University of Western Ontario, London, Canada.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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