HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: M600183-JLR200v1 47/10/2268    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Abe, A. Articles by Shayman, J. A. Search for Related Content PubMed PubMed Citation Articles by Abe, A. Articles by Shayman, J. A. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol. 47, 2268-2279, October 2006
Copyright © 2006 by American Society for Biochemistry and Molecular Biology

Positional specificity of lysosomal phospholipase A₂

Akira Abe^*, Miki Hiraoka and James A. Shayman^1,*

^* Nephrology Division, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-0676
Ophthalmology Department, Nippon Medical School, 1-1-5 Sendagi, Bukyo-ku, Tokyo 113-8603, Japan

Published, JLR Papers in Press, July 12, 2006.

¹ To whom correspondence should be addressed. e-mail: jshayman{at}umich.edu

Lysosomal phospholipase A₂ (Lpla2) is highly expressed in alveolar macrophages and may mediate the phospholipid metabolism of surfactant. Studies on the properties of this phospholipase are consistent with the presence of both phospholipase A₁ and phospholipase A₂ activities. These activities were studied through the production of O-acyl compounds, produced by the transacylase activity of Lpla2. Liposomes containing POPC and N-acetylsphingosine (NAS) were incubated with the soluble fraction obtained from MDCK cells stably transfected with the mouse Lpla2 gene. Two 1-O-acyl-NASs, 1-O-palmitoyl-NAS and 1-O-oleoyl-NAS, were produced by Lpla2. The formation rate of 1-O-oleoyl-NAS was 2.5-fold that of 1-O-palmitoyl-NAS. When 1-oleoyl-2-palmitoyl-sn-glycero-3-phosphocholine (OPPC) was used, the formation rate of 1-O-oleoyl-NAS was 5-fold higher than that of 1-O-palmitoyl-NAS. Thus, Lpla2 can act on acyl groups at both sn-1 and sn-2 positions of POPC and OPPC. When 1-palmitoyl-2-unsaturated acyl-sn-glycero-3-phosphocholines were used as acyl donors, the transacylation of the acyl group from the sn-2 position to NAS was preferred to that of the palmitoyl group from the sn-1 position. An exception was observed for 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC), for which the formation rate of 1-O-palmitoyl-NAS from PAPC was 4-fold greater than that of 1-O-arachidonoyl-NAS. Thus, Lpla2 has broad positional specificity for the sn-1 and sn-2 acyl groups in phosphatidylcholine and phosphatidylethanolamine.

Supplementary key words alveolar macrophage • phosphatidylcholine • phosphatidylethanolamine • transacylation • surfactant

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				B. P. Hurley and B. A. McCormick Multiple Roles of Phospholipase A2 during Lung Infection and Inflammation Infect. Immun., June 1, 2008; 76(6): 2259 - 2272. [Full Text] [PDF]

				A. Abe, M. Hiraoka, and J. A. Shayman The acylation of lipophilic alcohols by lysosomal phospholipase A2 J. Lipid Res., October 1, 2007; 48(10): 2255 - 2263. [Abstract] [Full Text] [PDF]