Publications

• The amino acid sequence of tauropine dehydrogenase from the polychaete Arabella iricolor.

  Kan-no N., Endo N., Moriyama S., Nagahisa E., Sato M.

  The amino acid sequence of tauropine dehydrogenase (EC 1.5.1.23) from the polychaete Arabella iricolor was determined by automated sequencing of fragments obtained by cleavage with lysyl endopeptidase, endoproteinase Glu-C, and cyanogen bromide. The purified enzyme contained two isoforms that diff ... >> More

  The amino acid sequence of tauropine dehydrogenase (EC 1.5.1.23) from the polychaete Arabella iricolor was determined by automated sequencing of fragments obtained by cleavage with lysyl endopeptidase, endoproteinase Glu-C, and cyanogen bromide. The purified enzyme contained two isoforms that differ only in the 41st amino acid residue (Thr or Ile). Although the sequence contained eight Cys residues, intrachain disulfide bonds were not found. Two possible N-linked glycosylation sites occur in the sequences, but the enzyme does not appear to contain bound carbohydrates. Based on these data, the two isoforms of Arabella tauropine dehydrogenase are simple proteins consisted of 396 amino acid residues with calculated molecular masses of 43,085.7 Da (Thr41 isoform) and 43,097.8 Da (Ile41 isoform). << Less

  Comp Biochem Physiol B Biochem Mol Biol 140:475-485(2005) [PubMed] [EuropePMC]

• Tauropine dehydrogenase from the sandworm Arabella iricolor (Polychaeta: Errantia): purification and characterization.

  Kanno N., Sato M., Nagahisa E., Sato Y.

  This is the first report of the purification of tauropine dehydrogenase (NAD: tauropine oxidoreductase) from a polychaete worm. In the sandworm Arabella iricolor Montagu (Polychaeta: Errantia), two forms of TaDH were detected: major component (pl = 7.5) and minor one (pl = 6.4). The major TaDH com ... >> More

  This is the first report of the purification of tauropine dehydrogenase (NAD: tauropine oxidoreductase) from a polychaete worm. In the sandworm Arabella iricolor Montagu (Polychaeta: Errantia), two forms of TaDH were detected: major component (pl = 7.5) and minor one (pl = 6.4). The major TaDH component was purified to homogeneity by means of (NH4)2SO4 precipitation, anion-exchange, affinity, chromatofocusing and hydrophobic chromatography, and characterized. From the molecular mass of 43.7 kDa obtained by rapid gel-filtration and that of 43.5 kDa by SDS-PAGE, the sandworm enzyme appeared to be a monomeric protein. Maximum rates of reduction of pyruvate and oxidation of tauropine were observed at pH 7.0 and 8.5, respectively. Pyruvate and taurine were preferred substrate for the enzyme. Apparent K(m) values determined using constant co-substrate concentrations were: 35.7 mM, 0.34 mM, and 0.036 mM for taurine, pyruvate and NADH, respectively, in the tauropine synthesizing reaction; and 4.8 mM and 0.051 mM for tauropine and NAD+, respectively, in the tauropine oxidizing reaction. The tauropine synthesizing reaction was subject to substrate inhibition by pyruvate: maximum rate was observed at 2.5-3.0 mM (inhibitory range of pyruvate concentration producing half-maximal rate was 26.8 mM). << Less

  Comp. Biochem. Physiol. 114:409-416(1996) [PubMed] [EuropePMC]

• Purification and properties of tauropine dehydrogenase from the shell adductor muscle of the ormer, Haliotis lamellosa.

  Gade G.

  Tauropine dehydrogenase (tauropine:NAD oxidoreductase) was purified from the shell adductor muscle of the ormer, Haliotis lamellosa. The enzyme was found to utilize stoichiometrically NADH as co-enzyme and pyruvate and taurine as substrates producing tauropine [rhodoic acid; N-(D-1-carboxyethyl)-t ... >> More

  Tauropine dehydrogenase (tauropine:NAD oxidoreductase) was purified from the shell adductor muscle of the ormer, Haliotis lamellosa. The enzyme was found to utilize stoichiometrically NADH as co-enzyme and pyruvate and taurine as substrates producing tauropine [rhodoic acid; N-(D-1-carboxyethyl)-taurine]. The enzyme was purified to a specific activity of 463 units/mg protein using a combination of ammonium sulphate fractionation, ion-exchange and affinity chromatography. The relative molecular mass was 38,000 +/-1000 when assessed by gel filtration on Ultrogel AcA 54 and 42,000 +/-150 by electrophoresis on 5-10% polyacrylamide gels in the presence of 1% sodium dodecyl sulphate; the data suggest a monomeric structure. Tauropine and pyruvate were found to be the preferred substrates. Among the amino acids tested for activity with the enzyme, only alanine is used as an alternative substrate, but with a rate less than 6% of the enzyme activity with taurine. Of the oxo acids tested, 2-oxobutyrate and 2-oxovalerate were also found to be substrates. Apparent Km values for the substrates NADH, pyruvate and taurine are 0.022 +/-0.003 mM, 0.64 +/- 0.07 mM and 64.7 +/-5.4 mM, respectively, at pH 7.0 and for the products, NAD+ and tauropine, are 0.29 +/- 0.01 mM and 9.04 +/-1.27 mM, respectively, at pH 8.3. Apparent Km values for both pyruvate and taurine decrease with increasing co-substrate (taurine or pyruvate) concentration. NAD+ and tauropine were found to be product inhibitors of the forward reaction. NAD+ was a competitive inhibitor of NADH, whereas tauropine gave a mixed type of inhibition with respect to pyruvate and taurine. Succinate was found to inhibit non-competitively with respect to taurine and pyruvate with an apparent Ki value in the physiological range of this anaerobic end product. The inhibition by L-lactate, not an end product in the ormer, was competitive with respect to pyruvate. The physiological role or tauropine dehydrogenase during anaerobiosis is discussed. << Less

  Eur J Biochem 160:311-318(1986) [PubMed] [EuropePMC]