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Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)

Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initia...

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Autores principales: Cao, Heping, Sethumadhavan, Kandan, Grimm, Casey C., Ullah, Abul H. J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159287/
https://www.ncbi.nlm.nih.gov/pubmed/25203006
http://dx.doi.org/10.1371/journal.pone.0106403
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author Cao, Heping
Sethumadhavan, Kandan
Grimm, Casey C.
Ullah, Abul H. J.
author_facet Cao, Heping
Sethumadhavan, Kandan
Grimm, Casey C.
Ullah, Abul H. J.
author_sort Cao, Heping
collection PubMed
description Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and P(i). PAPs are typically categorized into two subfamilies: Mg(2+)-dependent soluble PAP and Mg(2+)-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg(2+)-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53–60°C and unaffected by up to 0.3 mM MgCl(2). The K(m) and V(max) values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na(3)VO(4), Triton X-100, FeSO(4) and CuSO(4), but stimulated by MnSO(4), ZnSO(4) and Co(NO(3))(2). In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg(2+)-independent enzyme in plants.
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spelling pubmed-41592872014-09-12 Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia) Cao, Heping Sethumadhavan, Kandan Grimm, Casey C. Ullah, Abul H. J. PLoS One Research Article Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and P(i). PAPs are typically categorized into two subfamilies: Mg(2+)-dependent soluble PAP and Mg(2+)-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg(2+)-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53–60°C and unaffected by up to 0.3 mM MgCl(2). The K(m) and V(max) values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na(3)VO(4), Triton X-100, FeSO(4) and CuSO(4), but stimulated by MnSO(4), ZnSO(4) and Co(NO(3))(2). In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg(2+)-independent enzyme in plants. Public Library of Science 2014-09-09 /pmc/articles/PMC4159287/ /pubmed/25203006 http://dx.doi.org/10.1371/journal.pone.0106403 Text en https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
spellingShingle Research Article
Cao, Heping
Sethumadhavan, Kandan
Grimm, Casey C.
Ullah, Abul H. J.
Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)
title Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)
title_full Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)
title_fullStr Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)
title_full_unstemmed Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)
title_short Characterization of a Soluble Phosphatidic Acid Phosphatase in Bitter Melon (Momordica charantia)
title_sort characterization of a soluble phosphatidic acid phosphatase in bitter melon (momordica charantia)
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159287/
https://www.ncbi.nlm.nih.gov/pubmed/25203006
http://dx.doi.org/10.1371/journal.pone.0106403
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