Subcellular localization of acyl carrier protein in leaf protoplasts of [spinach] Spinacia oleracea

This communication demonstrates that all de novo fatty acid biosynthesis in spinach leaf cells requires acyl carrier protein (ACP) and occurs specifically in the chloroplasts. Antibodies raised to purified spinach ACP inhibited at least 98% of malonyl CoA-dependent fatty acid synthesis by spinach le...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1979-03, Vol.76 (3), p.1194-1198
Main Authors: Ohlrogge, J.B, Kuhn, D.N, Stumpf, P.K
Format: Article
Language:English
Subjects:
Acyl Carrier Protein - metabolism
Antibodies
Biosynthesis
Cell Fractionation
Chlorophylls
Chloroplasts
Cross Reactions
Enzymes
Fatty acids
Fatty Acids - biosynthesis
Organelles
Plant cells
Plants - metabolism
Protoplasts
Protoplasts - metabolism
Radioimmunoassay
Spinach
Subcellular Fractions - metabolism
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This communication demonstrates that all de novo fatty acid biosynthesis in spinach leaf cells requires acyl carrier protein (ACP) and occurs specifically in the chloroplasts. Antibodies raised to purified spinach ACP inhibited at least 98% of malonyl CoA-dependent fatty acid synthesis by spinach leaf homogenates. Therefore, the presence of ACP in a compartment of the spinach leaf cell would serve as a marker for de novo fatty acid biosynthesis. A radioimmunoassay capable of detecting 10-15mol (10-11g) of spinach ACP was developed to measure the levels of ACP in leaf cell components isolated by sucrose gradient centrifugation of a gentle lysate of spinach leaf protoplasts. All of the ACP of the leaf cell could be attributed to the chloroplast. Less than 1% of the ACP associated with chloroplasts resulted from binding of free ACP to chloroplasts. Of interest, ACP from Escherichia coli, soybean, and sunflower showed only partial crossreactivity with spinach ACP by the radioimmunoassay. These results strongly suggest that, in the leaf cell, chloroplasts are the sole site for the de novo synthesis of C16and C18fatty acids. These fatty acids are then transported into the cytoplasm for further modification and are either inserted into extrachloroplastic membrane lipids or returned to the chloroplast for insertion into lamellar membrane lipids.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.76.3.1194