Document Detail

Role of acidic Ca2+-independent phospholipase A2 in synthesis of lung dipalmitoyl phosphatidylcholine.
MedLine Citation:
PMID:  9124374     Owner:  NLM     Status:  MEDLINE    
Dipalmitoyl phosphatidylcholine (deltaPC) synthesis by lung epithelium occurs in part by a deacylation/reacylation pathway utilizing phospholipase A2 (PLA2) and an acyl transferase. The role of acidic Ca2+-independent PLA2 (aiPLA2) in this pathway was investigated using a transition-state analog enzyme inhibitor [1-hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol (MJ33)]. Granular pneumocytes were isolated from rat lung with elastase and were maintained in primary culture for 24 h on microporous membranes in the presence of radiolabeled choline or free fatty acids (palmitate plus oleate). Disaturated phosphatidylcholine (DSPC) was determined by osmication chromatography. Incorporation (nmol/mg protein) into DSPC at 24 h incubation was 11.9 +/- 0.2 for [3H]choline and 12.1 +/- 0.04 for [3H]palmitate. In the presence of 3 mol% MJ33, incorporation of [3H] choline and [3H]palmitate was decreased by 37 and 69%, respectively, and DSPC pool size (microg/mg cell protein) decreased by 9% (P < 0.05). A similar decrease in radiolabel incorporation was observed with 2 h of incubation. The presence of p-bromophenacyl bromide (20 microm) had a significantly smaller effect that was additive with that of MJ33. After 24 h of labeling and 4 h of chase with unlabeled substrate, there was a significant decrease of radiolabel in DSPC that was inhibited by MJ33. Under all experimental conditions, MJ33 resulted in either no change or a modest increase of radiolabel in the cellular unsaturated PC fraction. These results indicate that aiPLA2 has a major role in DSPC synthesis by granular pneumocytes.
A B Fisher; C Dodia
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  272     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Feb 
Date Detail:
Created Date:  1997-04-24     Completed Date:  1997-04-24     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  L238-43     Citation Subset:  IM    
Institute for Environmental Medicine, University of Pennsylvania Medical Center, Philadelphia 19104, USA.
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MeSH Terms
1,2-Dipalmitoylphosphatidylcholine / biosynthesis*
Acids / metabolism*
Calcium / physiology*
Enzyme Inhibitors / pharmacology
Fatty Acids / pharmacology
Glycerophosphates / pharmacology
Lung / cytology,  drug effects,  metabolism*
Methylamines / pharmacology
Phospholipases A / antagonists & inhibitors,  physiology*
Phospholipases A2
Rats, Sprague-Dawley
Substrate Specificity
Grant Support
Reg. No./Substance:
0/Acids; 0/Enzyme Inhibitors; 0/Fatty Acids; 0/Glycerophosphates; 0/Methylamines; 137464-44-9/1-hexadecyl-3-trifluoroethylglycero-sn-2-phosphomethanol; 2644-64-6/1,2-Dipalmitoylphosphatidylcholine; 74-89-5/methylamine; 7440-70-2/Calcium; EC 3.1.1.-/Phospholipases A; EC A2

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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