Peptide mapping of protein bands from polyacrylamide gel electrophoresis by chemical cleavage in gel pieces and re-electrophoresis.
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Aspartic Acid↗
Biomedical subjects
R Jaussi
Publications and source records attributed to R Jaussi.
Biosynthesis of aspartate aminotransferases. Both the higher molecular weight precursor of mitochondrial aspartate aminotransferase and the cytosolic isoenzyme are synthesized on free polysomes.
The site of synthesis of the higher molecular weight precursor of mitochondrial aspartate aminotransferase (Sonderegger, P., Jaussi, R., and Christen, P. (1980) Biochem. Biophys. Res. Commun. 94, 1256-1260) has been determined by separation of free and membrane-bound polysomes under ionic conditions imitating the intracellular milieu and in vitro read-out translation of the two polysome fractions in a rabbit reticulocyte lysate. The amounts of the precursor of mitochondrial aspartate aminotransferase synthesized by free and membrane-bound polysomes were compared with the relative extent of the synthesized of cytosolic aspartate aminotransferase in the same fractions. Only a small (less than 10% of total) and for both isoenzymes quantitatively equivalent fraction was found to be produced by the membrane-bound polysome fraction; very likely, it has to be attributed to contaminating free polysomes. Apparently, the import of mitochondrial aspartate aminotransferase into the mitochondria does not involve an association of polysomes with intracellular membranes.
Animals↗
Cell-free synthesis of the one-chain precursor of a major intrinsic protein complex of the small-intestinal brush border membrane (pro-sucrase-isomaltase).
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Animals↗
Cell-free synthesis of a putative precursor of mitochondrial aspartate aminotransferase with higher molecular weight.
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Animals↗
Isolation of the major toxic protein from the skin venom of the crested newt, Triturus cristatus.
A new protein, of molecular weight 160,000, was isolated from the skin venom of the crested newt and partially characterized by bioassays and biochemical methods. This protein shows the same functional properties as the crude venom, which produces convulsions in mice and is cytotoxic.
Amphibian Venoms↗
Enzyme-linked immunosorbent assay for measurement of JNK, ERK, and p38 kinase activities.
A rapid enzyme-linked immunosorbent assay for the enzyme activity measurement of three well-known mitogen-activated protein (MAP) kinases, JNK2, ERK2, and p38 is described. The assay involves immobilization of the respective kinase substrates c-Jun, Elk1, or ATF2 on microtiter plates, addition of the kinase reaction mixture, and measurement of substrate phosphorylation using phospho-epitope-specific antibodies. This novel procedure represents a marked improvement to conventional radioactive MAP kinase assays in terms of quantification, precision, performance at physiological ATP concentration, high throughput, time consumption and amenability to automation. In addition to the standard solid phase assay using plastic-bound protein substrates, we developed an alternative solution phase protocol using soluble protein substrates. By comparing the results of the two assays, we found that MAP kinases retained much of their substrate specificity in the phosphorylation of immobilized protein substrates. Interestingly, we observed a strong preference of JNK2 and p38 for the phosphorylation of dimeric over monomeric substrates. We further characterized the kinase inhibitory activity of olomoucine, staurosporine, and SB 203580 for JNK2, ERK2, and p38. Taken together, this assay could assist in the biochemical characterization of MAP kinases and in identifying potent and specific inhibitors of these enzymes.
3T3 Cells↗