Transport dicarboxylate system

The transporters have overlapping specificities. Thus, there is one transporter (called system L) for leucine and neutral amino acids with branched or aromatic side chains, another for basic amino acids (the Ly system), and a low-activity carrier (the dicarboxylate system) for dicarboxylic amino acids. 

Six S, SC Andrews, G Unden, JR Guest (1994) Escherichia coli possesses two homologous anaerobic C4-dicarboxylate membrane transporters (Dcua and Dcub) distinct from the aerobic dicarboxylate transport system (Dcf). J Bacterial 176 6470-6478. 

HambUn, M.J. Shaw, J.C. Kelly, D.J. Sequence analysis and interposon mutagenesis of a sensor-kinase (DctS) and response-regulator (DctR) controlling synthesis of the high-affinity C4-dicarboxylate transport system in Rhodobacter capsulatus. Mol. Cen. Cenet., 237, 215-224 (1993)... 

H+ cotransporters of low specificity.500 A Cl- / oxalate transporter is one of several ion exchange proteins in the kidney.501 Transport systems for ADP, phosphate, dicarboxylates, and other anions are very active in mitochondrial membranes (Chapter 18). 

For an effective symbiotic state, the plant and the microsymbiont must maintain a constant metabolic flow of carbon and nitrogen. While the bacteroids function as an engine for nitrogen fixation the fuel comes from the plant. Dicarboxylic acids are the primary carbon sources fed to the bacteroids by the plant. This unidirectional flow of carbon must be controlled by the PBM. Recently, several specific carbon and amino acid transport systems have been identified in the PBM using isolated peribac-teroid units (PBU Day et al., 1990). Thus, in order for the host plant to house endosymbiotic bacteria and support their metabolic needs, a number of nodulin genes must be induced to support the ontogeny and function of the nodules. 

Carrier-mediated membrane transport proteins on the RPE selectively transport nutrients, metabolites, and xenobiotics between the choriocapillaris and the cells of the distal retina, and include amino acid [33 35], peptide [36], dicarboxylate, glucose [37], monocarboxylic acid [38,39], nucleoside[40], and organic anion and organic cation [41] transporters. Membrane barriers such as the efflux pumps, including multidrug resistance protein (P-gp), and multidrug resistance-associated protein (MRP) pumps have also been identified on the RPE. Exploitation of these transport systems may be the key to circumventing the outer BRB. 

Carrigan CN, Esslinger CS, Bartlett RD, Bridges RJ, Thompson CM (1999) Quinoline-2,4-dicarboxylic acids synthesis and evaluation as inhibitors of the glutamate vesicular transport system. Bioorg Med Chem Lett 9 2607-2612. 

A direct K+ requirement for translocation has, however, been reported for glutamic acid transport in brain (Kanner and Schuldiner, 1987 Carlson et al., 1989). The dicarboxylic amino acids appear to be transported largely by specific transporters which do not participate in neutral amino acid transport. Recent studies, both in reconstituted systems and the expression of the cloned transporter, have confirmed the K+ requirement (see below). 

Several additional mitochondrial carrier systems have been reconstituted into active form in proteoliposomes, using as starting material a crude neutral detergent mixture of membrane proteins from submitochondrial particles. These include the citrate transporter [203], the dicarboxylate carrier [204], and the carnitine transporters [202]. These reconstitution activities could be used as a basis for further purification and structural studies, but such studies have not yet been reported. 

Electron transport across organised bilayers is an integral part of biological energy storage systems such as photosynthesis and provides a means of controlling back electron transfer and of separation of the products of redox reactions. Esters of 2,l,3-benzothiadiazole-4,7-dicarboxylic acid (481) have been used to study the transfer of electrons from 2-(morpholino)ethanesulfonic acid (MES) to 1,5-anthraquinone disulfonate in micelles or across vesicle bilayers. The esters absorb the light, accept an electron from MES and transfer it to the... 

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