Bacteriorhodopsin: a biological material for information processing.
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Bacteriorhodopsins↗
Biomedical subjects
N Hampp
Publications and source records attributed to N Hampp.
Indomethacin ion-selective electrode based on a bis(triphenylphosphoranylidene)ammonium-indomethacin complex.
The properties of an ion-selective electrode for indomethacin based on the bis(triphenylphosphoranylidene)ammonium-indomethacin ion-pair complex in a poly(vinyl chloride) membrane are described. The detection limit found for indomethacin at pH 7.0 was 2 x 10(-5) mol l-1 (6.4 micrograms ml-1) and the linear range was determined to be between 5 x 10(-5) and greater than or equal to 10(-3) mol l-1. The selectivity coefficients observed for organic anions of different lipophilicity were 10(-1.1) for naproxenate, 10(-0.75) for salicylate and less than 10(-4) for tartrate. Cationic organic and inorganic ions showed negligible interference with selectivity coefficients of less than 10(-4). A strong electrode response was observed for the inorganic anions IO4-, ClO4- and SCN- with selectivity coefficients of up to 10(+0.9). Very low detection limits, e.g., 6 x 10(-7) mol l-1 (60 ng ml-1) for ClO4- were found. The selectivity for inorganic anions was close to the Hofmeister series.
Electrodes↗
Determination of ethaverine and papaverine using ion-selective electrodes.
Ion-selective poly(vinyl chloride) membrane electrodes for the opium alkaloids papaverine and ethaverine are presented. The electrode membranes contain ion pairs of the alkaloids with the anionic counter ion tetraphenylborate. The detection limits for all electrodes were approximately 2 x 10(-6) mol dm-3 at pH 5.0 in 100 mmol dm-3 buffered solutions and the measured slopes were close to the values theoretically expected. The selectivity coefficient observed for the ethaverine-tetraphenylborate electrode is 10(-1.1) with respect to papaverine. The suitability of the membranes for single-use electrodes is discussed.
Electrochemistry↗
The cDNA clone for strictosidine synthase from Rauvolfia serpentina. DNA sequence determination and expression in Escherichia coli.
The cDNA clone for strictosidine synthase, the enzyme which catalyzes the stereospecific condensation of tryptamine with secologanin to form the key intermediate in indole alkaloid biosynthesis, strictosidine, has been identified with a synthetic oligodeoxynucleotide hybridization probe in a lambda gt11 cDNA library of cultured cells of Rauvolfia serpentina. The DNA has been sequenced, revealing an open reading frame of 1032 base pairs encoding 344 amino acids. The sequence of 60 nucleotides in the 5'-flanking region has been determined by primer extension analysis. The encoded protein has been expressed in E. coli DH5 as detected by immunoblotting of protein extracts with antibodies raised against the native enzyme.
Amino Acid Sequence↗