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

J. Biol. Chem., Vol. 278, Issue 23, 20731-20737, June 6, 2003

This Article Full Text Full Text (PDF) All Versions of this Article: 278/23/20731    most recent M302894200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Quinlivan, E. P. Articles by Hanson, A. D. Search for Related Content PubMed PubMed Citation Articles by Quinlivan, E. P. Articles by Hanson, A. D. Social Bookmarking                      What's this?

The Folate Precursor p-Aminobenzoate Is Reversibly Converted to Its Glucose Ester in the Plant Cytosol^*

Eoin P. Quinlivan , Sanja Roje , Gilles Basset , Yair Shachar-Hill ¶, Jesse F. Gregory, III  and Andrew D. Hanson  ||

From the Food Science and Human Nutrition Department and the Horticultural Sciences Department, University of Florida, Gainesville, Florida 32611 and the ^¶Plant Biology Department, Michigan State University, East Lansing, Michigan 48824

Plants synthesize p-aminobenzoate (pABA) in chloroplasts and use it for folate synthesis in mitochondria. It has generally been supposed that pABA exists as the free acid in plant cells and that it moves between organelles in this form. Here we show that fruits and leaves of tomato and leaves of a diverse range of other plants have a high capacity to convert exogenously supplied pABA to its -D-glucopyranosyl ester (pABA-Glc), whereas yeast and Escherichia coli do not. High performance liquid chromatography analysis indicated that much of the endogenous pABA in fruit and leaf tissues is esterified and that the total pool of pABA (free plus esterified) varies greatly between tissues (from 0.2 to 11 nmol g^–1 of fresh weight). UDP-glucose:pABA glucosyltransferase activity was readily detected in fruit and leaf extracts, and the reaction was found to be freely reversible. p-Aminobenzoic acid -D-glucopyranosyl ester esterase activity was also detected in extracts. Subcellular fractionation indicated that the glucosyltransferase and esterase activities are predominantly if not solely cytosolic. Taken together, these results show that reversible formation of pABA-Glc in the cytosol is interposed between pABA production in chloroplasts and pABA consumption in mitochondria. As pABA is a hydrophobic weak acid, its uncharged form is membrane-permeant, and its anion is consequently prone to distribute itself spontaneously among subcellular compartments according to their pH. Esterification of pABA may eliminate such errant behavior and provide a readily reclaimable storage form of pABA as well as a substrate for membrane transporters.

Received for publication, March 21, 2003 , and in revised form, March 28, 2003.

^* This work was supported in part by the Florida Agricultural Experimental Station, by an endowment from the C. V. Griffin, Sr. Foundation, and by Grant MCB-0129944 from the National Science Foundation, and approved for publication as Journal Series no. R-09397. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

^|| To whom correspondence should be addressed: Horticultural Sciences Dept., University of Florida, P. O. Box 110690, Gainesville, FL 32611. Tel.: 352-392-1928 (ext. 334); Fax: 352-392-5653; E-mail: adha{at}mail.ifas.ufl.edu.

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

This article has been cited by other articles:

				F. J. Sandoval, Y. Zhang, and S. Roje Flavin Nucleotide Metabolism in Plants: MONOFUNCTIONAL ENZYMES SYNTHESIZE FAD IN PLASTIDS J. Biol. Chem., November 7, 2008; 283(45): 30890 - 30900. [Abstract] [Full Text] [PDF]

				A. Eudes, G. G. Bozzo, J. C. Waller, V. Naponelli, E.-K. Lim, D. J. Bowles, J. F. Gregory III, and A. D. Hanson Metabolism of the Folate Precursor p-Aminobenzoate in Plants: GLUCOSE ESTER FORMATION AND VACUOLAR STORAGE J. Biol. Chem., May 30, 2008; 283(22): 15451 - 15459. [Abstract] [Full Text] [PDF]

				J. Botet, L. Mateos, J. L. Revuelta, and M. A. Santos A Chemogenomic Screening of Sulfanilamide-Hypersensitive Saccharomyces cerevisiae Mutants Uncovers ABZ2, the Gene Encoding a Fungal Aminodeoxychorismate Lyase Eukaryot. Cell, November 1, 2007; 6(11): 2102 - 2111. [Abstract] [Full Text] [PDF]

				R. I. Diaz de la Garza, J. F. Gregory III, and A. D. Hanson From the Cover: Folate biofortification of tomato fruit PNAS, March 6, 2007; 104(10): 4218 - 4222. [Abstract] [Full Text] [PDF]

				S. M. J. Klaus, E. R. S. Kunji, G. G. Bozzo, A. Noiriel, R. D. de la Garza, G. J. C. Basset, S. Ravanel, F. Rebeille, J. F. Gregory III, and A. D. Hanson Higher Plant Plastids and Cyanobacteria Have Folate Carriers Related to Those of Trypanosomatids J. Biol. Chem., November 18, 2005; 280(46): 38457 - 38463. [Abstract] [Full Text] [PDF]

				M. Hasumura, T. Imai, T. Takizawa, M. Ueda, J. Onose, and M. Hirose Promotion of Thyroid Carcinogenesis by para-aminobenzoic Acid in Rats Initiated with N-bis(2-hydroxypropyl)nitrosamine Toxicol. Sci., July 1, 2005; 86(1): 61 - 67. [Abstract] [Full Text] [PDF]

				G. J. C. Basset, E. P. Quinlivan, J. F. Gregory III, and A. D. Hanson Folate Synthesis and Metabolism in Plants and Prospects For Biofortification Crop Sci., January 31, 2005; 45(2): 449 - 453. [Abstract] [Full Text] [PDF]

				R. D. de la Garza, E. P. Quinlivan, S. M. J. Klaus, G. J. C. Basset, J. F. Gregory III, and A. D. Hanson Folate biofortification in tomatoes by engineering the pteridine branch of folate synthesis PNAS, September 21, 2004; 101(38): 13720 - 13725. [Abstract] [Full Text] [PDF]

				T. Hossain, I. Rosenberg, J. Selhub, G. Kishore, R. Beachy, and K. Schubert Enhancement of folates in plants through metabolic engineering PNAS, April 6, 2004; 101(14): 5158 - 5163. [Abstract] [Full Text] [PDF]

				G. J. C. Basset, E. P. Quinlivan, S. Ravanel, F. Rebeille, B. P. Nichols, K. Shinozaki, M. Seki, L. C. Adams-Phillips, J. J. Giovannoni, J. F. Gregory III, et al. Folate synthesis in plants: The p-aminobenzoate branch is initiated by a bifunctional PabA-PabB protein that is targeted to plastids PNAS, February 10, 2004; 101(6): 1496 - 1501. [Abstract] [Full Text] [PDF]