Biomaterial Database

Alpha-methyl-L-glutamic acid uptake by high affinity dicarboxylic amino acid transport system in Streptococcus faecalis. 1975

J T Holden, and N M Utech, and K G Reid

The transport of alpha-methyl-L-glutamic acid was studied in Streptococcus faecalis. Energey-dependent uptake against substantial concentration gradients was observed. Kinetic experiments indicated that, in contrast to L-glutamic acid, only a single catalytic component (high affinity) and a diffusion controlled process participated in alpha-methyl-L-glutamic acid uptake. At concentrations up to 10 mM, alpha-methyl-glutamate transport was almost completely abolished in a mutant strain lacking a high affinity dicarboxylic amino acid transport system. In competition experiments, alpha-methylglutamic acid antagonized glutamate uptake via the high affinity system, and only slightly via the low affinity system. Column chromatography of cell extracts showed that very little (approx. 5%) of the accumulated amino acid was converted to metabolites during short term incubations. These studies indicate that, at concentrations up to 3-5 mM, alpha-methyl-L-glutamic acid can be used as a specific, relatively metabolically inert substrate of the high affinity dicarboxylic amino acid transport system in S. faecalis.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D004058	Diffusion	The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.	Diffusions
D005971	Glutamates	Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure.	Glutamic Acid Derivatives,Glutamic Acids,Glutaminic Acids
D000600	Amino Acids, Dicarboxylic		Dicarboxylic Amino Acids,Acids, Dicarboxylic Amino
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill
D013293	Enterococcus faecalis	A species of gram-positive, coccoid bacteria commonly isolated from clinical specimens and the human intestinal tract. Most strains are nonhemolytic.	Streptococcus Group D,Streptococcus faecalis
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor