Phospholipid:diacylglycerol acyltransferase: an enzyme that catalyzes the acyl-CoA-independent formation of triacylglycerol in yeast and plants

Research output: Contribution to journalArticle

Abstract

Triacylglycerol (TAG) is known to be synthesized in a reaction that uses acyl-CoA as acyl donor and diacylglycerol (DAG) as acceptor, and which is catalyzed by the enzyme acyl-CoA:diacylglycerol acyltransferase. We have found that some plants and yeast also have an acyl-CoA-independent mechanism for TAG synthesis, which uses phospholipids as acyl donors and DAG as acceptor. This reaction is catalyzed by an enzyme that we call phospholipid:diacylglycerol acyltransferase, or PDAT. PDAT was characterized in microsomal preparations from three different oil seeds: sunflower, castor bean, and Crepis palaestina. We found that the specificity of the enzyme for the acyl group in the phospholipid varies between these species. Thus, C. palaestina PDAT preferentially incorporates vernoloyl groups into TAG, whereas PDAT from castor bean incorporates both ricinoleoyl and vernoloyl groups. We further found that PDAT activity also is present in yeast microsomes. The substrate specificity of this PDAT depends on the head group of the acyl donor, the acyl group transferred, and the acyl chains of the acceptor DAG. The gene encoding the enzyme was identified. The encoded PDAT protein is related to lecithin:cholesterol acyltransferase, which catalyzes the acyl-CoA-independent synthesis of cholesterol esters. However, budding yeast PDAT and its relatives in fission yeast and Arabidopsis form a distinct branch within this protein superfamily, indicating that a separate PDAT enzyme arose at an early point in evolution.

Details

Authors
  • A Dahlqvist
  • U Ståhl
  • Marit Lenman
  • A Banas
  • M Lee
  • L Sandager
  • H Ronne
  • S Stymne
External organisations
  • External Organization - Unknown
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Biological Sciences
Original languageEnglish
Pages (from-to)6487-6492
JournalProceedings of the National Academy of Sciences
Volume97
Issue number12
Publication statusPublished - 2000
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Department of Cell and Organism Biology (Closed 2011.) (011002100)