Biomaterial Database

Regulation of Na+-H+ exchange by transmethylation reactions in rat colonic brush-border membranes. 1986

P K Dudeja, and E S Foster, and T A Brasitus

Incubation of rat colonic brush-border membrane vesicles with 200 microM S-adenosyl-L-[Me-3H]methionine resulted in the labeling of both membrane phospholipids and proteins. This labeling was decreased approximately 50% by the methylation inhibitor S-adenosyl-L-homocysteine (2 mM). Utilizing the pH-sensitive fluorescent dye, acridine orange, as a means of determining Na+-H+ exchange, S-adenosyl-L-methionine (200 microM) significantly increased sodium-stimulated proton efflux in these vesicles at all concentrations of sodium (2.5-50 mM) tested. Examination of the kinetic parameters for sodium-stimulated proton efflux in the presence and absence of 200 microM S-adenosyl-L-methionine revealed that the methyl donor increased the Vmax for this exchange mechanism (expressed in arbitrary fluorescence units) by approx. 36% but did not influence its Km for sodium. S-Adenosyl-L-homocysteine (2 mM) inhibited S-adenosyl-L-methionine-mediated stimulation of this exchange process. The results demonstrate that methylation of membrane phospholipids and/or proteins can modulate Na+-H+ exchange in rat colonic brush-border membrane vesicles.

UI	MeSH Term	Description	Entries
D007413	Intestinal Mucosa	Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.	Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D008560	Membrane Fluidity	The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.	Bilayer Fluidity,Bilayer Fluidities,Fluidities, Bilayer,Fluidities, Membrane,Fluidity, Bilayer,Fluidity, Membrane,Membrane Fluidities
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D008745	Methylation	Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)	Methylations
D008871	Microvilli	Minute projections of cell membranes which greatly increase the surface area of the cell.	Brush Border,Striated Border,Border, Brush,Border, Striated,Borders, Brush,Borders, Striated,Brush Borders,Microvillus,Striated Borders
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D003106	Colon	The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.	Appendix Epiploica,Taenia Coli,Omental Appendices,Omental Appendix,Appendices, Omental,Appendix, Omental
D005454	Fluorescence Polarization	Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.	Anisotropy, Fluorescence,Fluorescence Anisotropy,Polarization, Fluorescence,Anisotropies, Fluorescence,Fluorescence Anisotropies,Fluorescence Polarizations,Polarizations, Fluorescence