Volume 25, Issue 3

Auf der Grundlage der Δ 1-n- ·Werte wurde die Anzahl der H 2 O-Moleküle, die von Metallionen bei der Komplexbildung mit NH 3 , CNS ⊖ , C 2 O 4 2⊖ und CH 2 C 2 O 4 2⊖ freigesetzt werden, bestimmt. Auf Grund dieser Daten wurde die Zusammensetzung der genannten Komplexionen in wäßriger Lösung und die Besonderheiten im Mechanismus der Anlagerung der Liganden durch die verschiedenen Kationen eingeschätzt.

A modified U.B.F.F. containing terms directly related to lone pair electrons, has been used to evaluate the potential constants of SeOF 2 . The value obtained for the Se-O stretching constant supports the double bond character of the bond. The lone pair-bond pair repulsion bears a fixed ratio to the non-bonded repulsion (F eF /F FF =1.24 and F eo /F oF =1.23) and this result is in agreement with earlier conclusions.

Es wurden die IR-Spektren von Triphenylsilyl-, Tri-p-tolylsilyl- und Tribenzylsilyl-Schwefelver-bindungen aufgenommen. Die Si-S-Valenzschwingungen dieser Verbindungen, die in folgenden Bereichen auftreten: Triphenylsilyl-Derivate 518 -572 c -1 , Tri-p-tolylsilyl-Derivate 519 -556 cm -1 , Tribenzylsilyl-Derivate 493 -530 cm -1 , werden diskutiert.

Durch Umsetzung von Trifluormethylsulfonylamid, CF 3 SO 2 NH 2 , mit Phosphorpentachlorid, Thionylchlorid und Schwefeltetrafluorid konnten die Verbindungen Trichlorphosphoranylidensulfonylmethyltrifluorid CF 3 SO 2 N=PCl 3 ,N-(Trifluormethylsulfonyl) schwefeloxidimid CF 3 SO 2 N=S=O und N-(Trifluormethylsulfonyl) iminoschwefeldifluorid CF 3 SO 2 N=SF 2 , hergestellt werden. Trifluormethylsulfonylfluorid reagiert mit Dimethylamin zum Trifluormethylsulfonyldimethylamid. Die neuen Verbindungen werden durch ihre Elementaranalyse, IR-Spektren und 19 F- und 1 H-KMR-Spektren charakterisiert.

Many metallochlorins can be reversibly oxidized in a one electron step. The midpoint oxidation potentials of magnesium-octaethyl-chlorin (MgOÄC), ZnOÄC, CuOÄC, NiOÁC and PdOÄC were found to be approximately 107, 197, 331, 356, and 422 mV vs. a saturated calomel electrode in chloroformmethanol. As with analogous metalloporphyrins the order of the oxidations potentials increases approximately linearly with the electronegativity values of the metal ions. The midpoint potentials of the one-electron oxidation of metallochlorins were found to be about 300 mV lower than those of analogous metallporphyrins. Sn (IV) -OÄC-dihydroxide and the monocation of OÄC could not be reversibly oxidized. A simple electrostatic argument can explain the oxidation behavior of these and other porphyrin derivatives. The more negative the ligand ring, the easier it is to remove an electron and vice versa. Thus experimental results point to a more ionic character of the metal-ligand bonds in metallochlorins as compared to metalloporphyrins. The unusual behavior of chlorophyll a and the optical and ESR-spectra of the resulting radicals are discussed. Some general properties of the chlorin- and porphyrin macrocycles are compared. Characteristic differences between the two ligand-systems are explained by the low basicity of the pyrrolin-nitrogen and the decreased symmetry of the ligand field in the chlorins.

Decarboxyschizopelt-Säure liefert bei der Entmethylierung mit Bortribromid Di-O-desmethyl-decarboxyschizopelt-Säure, die eine positive Gibbssche Reaktion zeigt. Daraus folgt für Schizopeltsäure Struktur 1 (1.6-Dimethoxy-3.8-dimethyl-7-methoxycarbonyl-dibenzofuran-4-carbonsäure).

The heartwood of Gmelina arborea has been extracted with benzene to isolate substances which may be responsible for its long durability. Two of the compounds isolated have been identified as ceryl alcohol and β-sitosterol. The structures of the remaining components are being further investigated.

The influence of Diethylstilboestrol (DES), Dihydro-DES, and some steroids on the enzymatic activity of glutamate dehydrogenase (GluDH) from beef liver was studied. In relation to the enzyme concentration in mg/ml the activity shows a maximum. This maximum fails when the turnover number is used as a measure for the enzyme activity. 10 -5 M DES inhibits the GluDH activity almost completely, Dihydro-DES, Cyproterone and Cyproterone-acetate show no inhibition. The influence of Progesterone and Testosterone is about 20% and 10% respectively of that of DES. Dialysis will overcome the inhibition completely, to a smaller rate (about 30%) the addition of 10 -3 M ADP too. It seems not to be necessary to suggest that there are two kinds of subunits of GluDH, the one corresponding to simple dilution, the other to treatment with DES.

Intraperitoneal injections of insulin into rats appeared to increase the rate of nuclear protein biosynthesis in rat liver. A one hour pulse of insulin stimulated the [ 14 C]-DL-leucine incorporation up to 50% compared to control values. A maximum (100% increase) was passed after 3 - 5 hours and the original rate of nuclear protein biosynthesis was obtained after 10 hours. The reactivity of insulin has been shown to be progressively diminished employing decreasing insulin concentrations. If [ 14 C] -DL- leucine was replaced by [ 3 H] -L-lysine no rise of nuclear protein biosynthesis, attributable to insulin, could be observed.

The RNA synthesized in isolated fat body cell nuclei of blowfly larvae under the influence of ecdysone and juvenile hormone was studied by sucrose density centrifugation and RNA-DNA-hybridization. RNA produced in isolated nuclei of larvae in the early third instar has a polydisperse sedimentation pattern, showing a maximum at about 14 S, while RNA synthesized in nuclei of larvae in a later developmental stage has, in average, lower sedimentation coefficients. No significant differences in sedimentation properties could be seen between RNA of control and hormone-treated nuclei. An investigation of the hybridization of RNA synthesized in hormone-treated nuclei showed that the RNA produced under the influence of ecdysone or juvenile hormone is qualitatively different from that of the controls. This points to a specific effect of the hormones on the genome. The antagonistic effect of ecdysone and juvenile hormone on RNA synthesis is discussed on the basis of hybridization studies.

A relatively heat-stable protein fraction from yeast has been isolated hydrolyzing GTP only in the presence of ribosomes. The ribosome-dependent GTPase does not catalyze peptide chain elongation by itself but is active in this process with a second protein fraction previously referred to as FII. The ribosome-dependent GTPase as well as the peptide chain elongation are inhibited by the antibiotic fusidic acid.

By ion echange analysis, dialysis and electrophoresis of double labelled ( 32 P and 51 Cr) chromic β-glycerophosphate complexes, the stability of the bond β-glycerophosphate-chromium under different conditions of olation and oxolation has been studied. The glycerophosphate can form complexes with 1 or 2 moles per chromium atom. Below pH 6.0 the complexes present cationic characteristics, while between pH 6.0 and pH 8.0 they behave as anions. The oxolation provokes a release of β-glycerophosphate from the complex. The physicochemical characteristics of these complexes are reflected in their behaviour “in vivo” when injected into mice.

Acridinorange and pyronine inhibit the uptake and phosphorylation of nucleosides. The same doses of inhibitor do not yet interfere with RNA synthesis. An inhibition of similar specificity concerning nucleoside uptake is observed by several pyrimido-pyrimidine and pteridine derivatives. This inhibition can be reversed only by such nucleosides which are phosphorylated by the same nucleoside kinase. Several nucleoside analogues were also tested. We conclude that the inhibitors are interfering with the kinase reaction in vivo. The propagation of fowl plague virus (KP) is inhibited only by high doses of pyronine, yet neither by the pyrimido-pyrimidines nor the pteridines tested.

In the proteins of cancer was found N-hydroxylation, that is the same way in spontaneous, chemical induced and virus-tumors. The analytical methods for the proof are described.

Cancerogene Nitrosamine werden unter dem Einfluß von Leber- und Nierenhomogenat primär in die entsprechenden Amidoxime umgelagert (II). Eine enzymatische Folgereaktion bewirkt Hydrolyse der Amidoxime zu primären Aminen und Hydroxamsäuren (III), während bei der langsam verlaufenden spontanen Hydrolyse auch Hydroxylamin abgespalten wird. Die Ausbeute an den Umlagerungsprodukten steigt mit dem Grad der cancerogenen Eigenschaften der einzelnen Nitrosamine. Bei quantitativer Aufarbeitung entsprach die Summe des zurückgewonnenen Nitrosamins und der Metabolisierungs-Produkte innerhalb der Fehlergrenze derjenigen des eingesetzten. Andere Metabolisierungen, die die Cancerogenes bewirken könnten, sind demnach unwahrscheinlich. Aus dem Einfluß verschiedener Effektoren kann auf die Beteiligung von Sulfhydryl-Fermenten geschlossen werden.

The preparation of uroporphyrin I and III by incubation of suspensions of P. shermanii in the presence of δ-amino-levulinic acid is described. The fermentation of P. shermanii in a synthetic medium yields coproporphyrin III. Furthermore the separation of uroporphyrin, hepta-, hexa-, penta- and tetracarboxylic porphyrins is described.