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'Tryptophan' in keywords
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1Author    Thomas Vom Bruch, Klaus-Heinrich RöhmRequires cookie*
 Title    Fluorescence Properties of Hog Kidney Aminoacylase I  
 Abstract    The state of the tryptophan residues of porcine kidney aminoacylase I (EC 3.5.1.14) was investigated by fluorescence spectroscopy and chemical modification. The pH-dependence of the fluorescence emission spectrum of the enzyme indicates that its native conformation prevails between pH 6 and 9.5. Within this range, the ionization of a residue with an apparent pKa of 7.1 quenches the enzyme fluorescence by about 15%. A similar reduction of fluorescence intensity accompanies the inactivation of aminoacylase I by treatment with N-bromosuccinimide in low excess. This suggests that in both cases a single tryptophyl residue out of eight residues per subunit is affected. Quenching by iodide revealed that, in the native conformation of the enzyme, 5—6 tryptophans per subunit are accessible, while 2—3 are buried within the protein. 8-Anilinonaph-thalene-L-sulfonate (ANS) is tightly bound to aminoacylase I (1 mol/mol dimer, K d < 1 PM). ANS binding does not interfere with substrate turnover; the spectroscopic properties of the amino-acylase-ANS complex are consistent with bound ANS being excited by radiationless energy transfer (RET) from buried tryptophyl residues of the enzyme. 
  Reference    Z. Naturforsch. 43c, 671—678 (1988); received June 3 1988 
  Published    1988 
  Keywords    Aminoacylase, Kidney, Tryptophan, Fluorescence, ANS 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0671.pdf 
 Identifier    ZNC-1988-43c-0671 
 Volume    43 
2Author    Y. Plancke, J.P H Énichart, J. L. BernierRequires cookie*
 Title    M echanism Proposal for a Fluorescent Am anitin Derivative Form ation  
 Abstract    A quantitative fluorimetric detection o f a-amanitin treat­ ed by H 3PO" is proposed. Spectra for both amanitin and tryptophan suggest an extended aromatic structure clearly confirmed by JH NMR spectrography. 
  Reference    Z. Naturforsch. 35c, 516—518 (1980); received October 22 1979/January 21 1980 
  Published    1980 
  Keywords    a-Amanitin, Tryptophan, Fluorimetric Detection, *H NMR 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0516_n.pdf 
 Identifier    ZNC-1980-35c-0516_n 
 Volume    35 
3Author    Thomas Rausch, Frieder Hofmann, Willy HilgenbergRequires cookie*
 Title    Kinetics of Oxidation of Tryptophan by Sodium Hypochlorite  
 Abstract    The oxidation of tryptophan to 3-indoleacetaldehyde with sodium hypochlorite was investigated with 14 C labelled DL-tryptophan. The reaction was performed under pseudo first order conditions. From the pH dependence of the reaction it was concluded that only the unprotonated tryptophan is converted to the aldehyde. The activation energy is 35 ± 2.2 (SE) kJ x mol -1 as derived from the Arrhenius plot. Variing the pH between 8.5 and 11.0 and the temperature in the range from 298 K to 318 K did not alter the selectivity of the reaction as confirmed by TLC of the product (purity > 90%). A possible reaction mechanism is proposed. 
  Reference    Z. Naturforsch. 36b, 359—361 (1981); received September 12 1980 
  Published    1981 
  Keywords    Tryptophan, Indoleacetaldehyde, Amino Acid Oxidation, Sodium Hypochlorite, Reaction Kinetics 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0359.pdf 
 Identifier    ZNB-1981-36b-0359 
 Volume    36 
4Author    Johannes Kösler, Monika Ohm, Wolfgang BarzRequires cookie*
 Title    Metabolism of Anthranilic Acid in Plant Cell Suspension Cultures  
 Abstract    Cell suspension cultures of some 12 plants were investigated for anthranilic acid metabolism. Rapid uptake of substrate is accompanied by partial excretion of anthranilic acid-N-glucoside and followed by predominant conversion into tryptophan. Ring cleavage reactions of anthranilate could not be observed but peroxidatic polymerisation occurred to a high percentage. Anthranilic acid-N-glucoside is not permanently stored by the cell cultures. 
  Reference    Z. Naturforsch. 33c, 368 (1978); received April 19 1978 
  Published    1978 
  Keywords    Anthranilic Acid, Plant Cell Suspension Cultures, Tryptophan, Glucoside, Degradation, Peroxidases 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0368.pdf 
 Identifier    ZNC-1978-33c-0368 
 Volume    33