Kupfer als Aktivator in Natriumchloridkristallen

Zusammenfassung Auf Grund polarographischer Analyse von Natriumchloridkristallen die auf verschiedene Weise durch Kupfer aktiviert waren, wird die Valenz des Kupfers in den Kristallen bestimmt. Weiter wird die Verteilung der Verunreinigungen in den Kristallen untersucht und die Abhängigkeit des Gehaltes an Verunreinigungen von der Geschwindigkeit der Züchtung des Kristalls und von der Zusammensetzung der Schmelze verfolgt.     

Arbeitstagung über die Physik und Chemie der Kristallphosphore in Berlin

Ohne Zusammenfassung

---

     

Über die Lage von Eingebauten Nickelionen in NaCl

The energy of built-in Ni^{+ +}-ions in an interstitial and in a substitutional position respectively in the crystals of NaCl as well as the energy effect of the building in were calculated. The comparison of results indicates the substitutional position to be more probable.

---

---

Der Verfasser dankt herzlich Herrn Dr. A.Bohun für die wertvollen Bemerkungen zu dieser Arbeit und Frl. Dipl.-Ing. H.Svobodová für die Durchführung der numerischen Berechnungen.     

Ligand-induced conformational heterogeneity of cytochrome P450 CYP119 identified by 2D NMR spectroscopy with the unnatural amino acid (13)C-p-methoxyphenylalanine

Conformational dynamics are thought to play an important role in ligand binding and catalysis by cytochrome P450 enzymes, but few techniques exist to examine them in molecular detail. Using a unique isotopic labeling strategy, we have site specifically inserted a (13)C-labeled unnatural amino acid residue, (13)C-p-methoxyphenylalanine (MeOF), into two different locations in the substrate binding region of the thermophilic cytochrome P450 enzyme CYP119. Surprisingly, in both cases the resonance signal from the ligand-free protein is represented by a doublet in the (1)H,(13)C-HSQC spectrum. Upon binding of 4-phenylimidazole, the signals from the initial resonances are reduced in favor of a single new resonance, in the case of the F162MeOF mutant, or two new resonances, in the case of the F153MeOF mutant. This represents the first direct physical evidence for the ligand-dependent existence of multiple P450 conformers simultaneously in solution. This general approach may be used to further illuminate the role that conformational dynamics plays in the complex enzymatic phenomena exhibited by P450 enzymes.     

Affinity chromatography of porcine pepsin on different types of immobilized 3,5-diiodo-L-tyrosine

The preparation of affinity sorbents containing immobilized iodinated derivatives of L-tyrosine for the affinity chromatography of porcine pepsin is described. The ligand was coupled either to Sepharose 4B or bead cellulose after the divinylsulfone activation or to Sepharose 4B after the activation with 2,4,6-trichloro-1,3,5-triazine. The highest capacity for porcine pepsin was found in the case of 3,5-diiodo-L-tyrosine coupled to divinylsulfone-activated Sepharose.