Abstract
The transport of [14C]glycyl-glycine (Gly-Gly) has been characterized in leaf discs from mature exporting leaves of broad bean (Vicia faba L.). In terms of glycine (Gly) equivalents, the rate of transport of Gly-Gly was similar to that of Gly uptake. Uptake of Gly-Gly was localized mainly in the mesophyll cells, with little accumulation in the veins. It was optimal at pH 6.0, sensitive to thiol reagents and metabolic inhibitors, and exhibited a single saturable phase with an apparent Michaelis constant of 16 mM. Gly-Gly did not inhibit the uptake of labeled Gly. Addition of Gly-Gly induced a concentration-dependent pH rise in the medium, showing that peptide uptake is mediated with proton co-transport. Gly-Gly also induced a concentration-dependent transmembrane depolarization of mesophyll cells with an apparent Michaelis constant of 15 mM. This depolarization was followed by a transient hyperpolarization. When present at a 10-fold excess, various peptides and tripeptides were able to inhibit Gly-Gly uptake with the following decreasing order of efficiency: Gly-Gly-Gly = leucine-Gly > Gly-tyrosine > Gly-glutamine = Gly-glutamic acid > Gly-phenylalanine > Gly-threonine > Gly-aspartic acid = Gly-asparagine = aspartic acid-Gly. Gly inhibited the uptake of Gly-Gly only slightly, whereas tetraGly and the tripeptide glutathione were not inhibitory. The dipeptides inhibiting Gly-Gly uptake also induced changes in the transmembrane potential difference of mesophyll cells and were able to affect in a complex way the response normally induced by Gly-Gly. Altogether, the data demonstrate the existence of a low-affinity, broad-specificity H+/peptide co-transporter at the plasma membrane of mesophyll cells. The physiological importance of this transporter for the exchange of nitrogenous compounds in mature leaves remains to be determined, as do the details of the electrophysiological events induced by the dipeptides.
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- Dantzig A. H., Tabas L. B., Bergin L. Cefaclor uptake by the proton-dependent dipeptide transport carrier of human intestinal Caco-2 cells and comparison to cephalexin uptake. Biochim Biophys Acta. 1992 Dec 9;1112(2):167–173. doi: 10.1016/0005-2736(92)90388-3. [DOI] [PubMed] [Google Scholar]
- Delrot S. Proton Fluxes Associated with Sugar Uptake in Vicia faba Leaf Tissues. Plant Physiol. 1981 Sep;68(3):706–711. doi: 10.1104/pp.68.3.706. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Higgins C. F., Payne J. W. The Peptide pools of germinating barley grains: relation to hydrolysis and transport of storage proteins. Plant Physiol. 1981 Apr;67(4):785–792. doi: 10.1104/pp.67.4.785. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hori R., Tomita Y., Katsura T., Yasuhara M., Inui K., Takano M. Transport of bestatin in rat renal brush-border membrane vesicles. Biochem Pharmacol. 1993 May 5;45(9):1763–1768. doi: 10.1016/0006-2952(93)90431-u. [DOI] [PubMed] [Google Scholar]
- Kunji E. R., Smid E. J., Plapp R., Poolman B., Konings W. N. Di-tripeptides and oligopeptides are taken up via distinct transport mechanisms in Lactococcus lactis. J Bacteriol. 1993 Apr;175(7):2052–2059. doi: 10.1128/jb.175.7.2052-2059.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marder R., Becker J. M., Naider F. Peptide transport in yeast: utilization of leucine- and lysine-containing peptides by Saccharomyces cerevisiae. J Bacteriol. 1977 Sep;131(3):906–916. doi: 10.1128/jb.131.3.906-916.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Matthews D. M. Intestinal absorption of peptides. Biochem Soc Trans. 1983 Dec;11(6):808–810. doi: 10.1042/bst0110808. [DOI] [PubMed] [Google Scholar]
- Sakr S., Lemoine R., Gaillard C., Delrot S. Effect of cutting on solute uptake by plasma membrane vesicles from sugar beet (Beta vulgaris L.) leaves. Plant Physiol. 1993 Sep;103(1):49–58. doi: 10.1104/pp.103.1.49. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Salmenkallio M., Sopanen T. Amino Acid and Peptide uptake in the scutella of germinating grains of barley, wheat, rice, and maize. Plant Physiol. 1989 Apr;89(4):1285–1291. doi: 10.1104/pp.89.4.1285. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Slack F. J., Mueller J. P., Sonenshein A. L. Mutations that relieve nutritional repression of the Bacillus subtilis dipeptide permease operon. J Bacteriol. 1993 Aug;175(15):4605–4614. doi: 10.1128/jb.175.15.4605-4614.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smid E. J., Driessen A. J., Konings W. N. Mechanism and energetics of dipeptide transport in membrane vesicles of Lactococcus lactis. J Bacteriol. 1989 Jan;171(1):292–298. doi: 10.1128/jb.171.1.292-298.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sopanen T., Burston D., Taylor E., Matthews D. M. Uptake of glycylglycine by the scutellum of germinating barley grain. Plant Physiol. 1978 Apr;61(4):630–633. doi: 10.1104/pp.61.4.630. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sopanen T. Development of Peptide Transport Activity in Barley Scutellum during Germination. Plant Physiol. 1979 Oct;64(4):570–574. doi: 10.1104/pp.64.4.570. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Verkamp E., Backman V. M., Björnsson J. M., Söll D., Eggertsson G. The periplasmic dipeptide permease system transports 5-aminolevulinic acid in Escherichia coli. J Bacteriol. 1993 Mar;175(5):1452–1456. doi: 10.1128/jb.175.5.1452-1456.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]