Beiträge zur allgemeinen Kolloidchemie. IX. Zur Konstitution des As2S3-Sols

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Structural aspects of phencyclidines: crystal structure and quantum mechanical calculations for 1-[1-(2-thienyl)cyclohexyl] piperidine and its hydrochloride

Crystal structure determinations for neutral and protonated phencyclidine, 1-[1-(2-thienyl)cyclohexyl] piperidine, show that the piperidine-axial conformer on the cyclohexane ring is present in the neutral compound, and that the piperidine-equatorial conformer in the protonated species. Quantum mechanical calculations in vacuo using ab initio techniques also arrive at the same conclusion. A search of the crystallographic literature via the Cambridge structural database reveals that all protonated phencyclidines assume the piperidine-equatorial conformation, and most neutral phencyclidines assume the piperidine-axial conformation.     

Intercalating Nucleic Acids with Pyrene Nucleotide Analogues as Next‐Nearest Neighbors for Excimer Fluorescence Detection of Single‐Point Mutations under Nonstringent Hybridization Conditions

Fluorescence and hybridization specificity is reported for intercalating nucleic acids (INAs), which are here oligodeoxynucleotides (ODNs) synthesized with insertions using (S)‐1‐[bis(4‐methoxyphenyl)(phenyl)methoxy]‐3‐[(pyren‐1‐yl)methoxy]propan‐2‐ol phosphoramidites. It is shown that an INA with two insertions placed as next‐nearest neighbors can be used for discrimination between nucleic acids and their single‐point mutants. Quenching of an excimer band at 480 nm is observed upon hybridizing to a complementary sequence, whereas the excimer band is present when the nucleobase pair between the two pyrene moieties is mismatched. It is the first example of a solution based on fluorescence detection of single‐point mutants that uses excimer formation and does not rely on stringent hybridization conditions. Furthermore, it is shown that INAs with pyrene insertions retain their sequence specificity in thermal melting.     

Intercalating Nucleic Acids Containing Insertions of Naphthalimide

In a study of linker‐length dependence, we evaluated naphthalimide (= 1H‐benzo[de]isoquinoline‐1,3(2H)‐dione) and 4‐bromonaphthalimide as intercalating nucleic acids. We used a vicinal dihydroxy system when incorporating the six different naphthalimide monomers into DNA, and found the minimum linker‐length to be five C‐atoms. With this length of the linker, naphthalimide was discriminating between DNA and RNA – stabilizing DNA, while destabilizing RNA. Furthermore, naphthalimide showed universal base character by hybridizing to the four natural bases with a range as narrow as 1.4°. When compared to pyrene, naphthalimide with the same linker‐length gave significantly higher thermal meltings when hybridized to DNA.     

Die Kjeldahl'sche Methode der Stickstoffbestimmung

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Copper/topaquinone-containing amine oxidase from lentil seedlings and bovine plasma: Catalytic mechanism and energetic domains

In this review the characteristics of the prosthetic group and the role of copper in amine oxidase purified from lentil seedlings are compared with the corresponding features of the amine oxidase isolated from bovine serum. Although both enzymes contain the same organic cofactor, the 6-hydroxydopa (2,4,5-trihydroxyphenethylamine) quinone, the catalytic cycle of lentil seedling amine oxidase operates through a Cu(I)-free-radical intermediate of the cofactor, whereas in bovine serum enzyme the radical form was not observed. The role of the metal in the catalytic mechanism of the two enzymes is also discussed. Moreover, the energetic domains and the effect of the temperature on activity, for both enzymes, are examined using differential scanning calorimetry.