Purification of ten-grammes amounts of [1-β-mercaptopropionic acid, 8-D-arginine]vasopressin (DDAVP) on a continuous free-flow electrophoresis. Chemical and pharmacological data of DDAVP and by-products

1978 ◽  
Vol 43 (2) ◽  
pp. 511-522 ◽  
Author(s):  
Milan Zaoral ◽  
Martin Flegel ◽  
Tomislav Barth ◽  
Alena Machová
Keyword(s):  
Arginine Vasopressin ◽  
Free Flow ◽  
Mercaptopropionic Acid ◽  
Pharmacological Data ◽  
By Products

Synthesis of [1-β-mercaptopropionic acid, 8-D-arginine]vasopressin (DDAVP) in solid phase. Simple optimalization

1979 ◽  
Vol 44 (4) ◽  
pp. 1173-1178 ◽  
Author(s):  
Viktor Krchňák ◽  
Milan Zaoral
Keyword(s):  
Arginine Vasopressin ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Experimental Conditions ◽  
Phase Synthesis ◽  
Mercaptopropionic Acid ◽  
Better Than

A series of solid-phase syntheses of the protected precursor II of DDAVP was carried out. Experimental conditions were developed under which practically pure II can reproducibly be obtained in yields better than 60%. The protected precursors of DDAVP obtained by liquid- and solid-phase synthesis and DDAVP samples obtained from these precursors were undistinguishable by conventional analytical or pharmacological assays.

[1-β-Mercaptopropionic acid, 8-α-amino-β-guanidinopropionic acid]vasopressin and [1-β-mercaptopropionic acid, 8-D-α-amino-β-guanidinopropionic acid]vasopressin; Analogs showing a high and specific antidiuretic effect

1979 ◽  
Vol 44 (8) ◽  
pp. 2447-2450 ◽  
Author(s):  
Milan Zaoral ◽  
Viktor Krchňák ◽  
František Brtník ◽  
Alena Machová ◽  
Jana Škopková
Keyword(s):  
Hydrogen Fluoride ◽  
Arginine Vasopressin ◽  
Liquid Hydrogen ◽  
Protecting Groups ◽  
Pressor Effect ◽  
Mercaptopropionic Acid ◽  
Antidiuretic Effect

β-Benzylthiopropionyl-tyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteine azide was condensed with prolyl-α-amino-nitroguanidinopropionyl-glycine amides (L2; D2) to β-benzylthiopropionyl-tyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteinyl-prolyl-α-amino-β-nitroguanidinopropionyl-glycine amides (L8; D8) which after removal of the protecting groups in liquid hydrogen fluoride, closure of the disulfide ring, desalting, and electrophoretic purification afforded [1-β-mercaptopropionic acid, 8-α-amino-β-guanidinopropionic acid]vasopressin (I) and [1-β-mercaptopropionic acid, 8-D-α-amino-β-guanidinopropionic acid]vasopressin (II). The antidiuretic effect of I (II) is about 10% of the effect of [1-β-mercaptopropionic acid, 8-D-arginine]vasopressin (DDAVP) (87 ± 8% DDAVP), the pressor effect is 49.5 I.U./mg (2.7 I.U./mg).

Effect of methylation of the hydroxyl group of tyrosine in [1-β-mercaptopropionic acid, 8-D-arginine]vasopressin on its biological effects

1979 ◽  
Vol 44 (5) ◽  
pp. 1642-1644 ◽  
Author(s):  
Viktor Krchňák ◽  
Milan Zaoral
Keyword(s):  
Arginine Vasopressin ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Biological Effects ◽  
Hydroxyl Group ◽  
Rat Uterus ◽  
Phase Synthesis ◽  
Mercaptopropionic Acid ◽  
Antidiuretic Effect

Using the method of solid-phase synthesis, S-benzyl-β-mercaptopropionyl-O-methyltyrosyl-phenylalanyl-glutaminyl-asparaginyl-S-benzylcysteinyl-prolyl-NG-p-toluenesulfonyl-D-arginyl-glycine amide (I) was prepared which after removal of the protecting groups, oxidation, and purification afforded [1-β-mercaptopropionic acid, 2-O-methyltyrosine, 8-D-arginine]vasopressin (II). II shows a low antidiuretic effect, c. 10 I.U./mg. It is without effect on rat uterus in vitro and on the blood pressure of rat in vitro.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Bright-Field Images (Ctem) of Phase Objects at High Resolution

1976 ◽  
Vol 34 ◽  
pp. 490-491 ◽  
Author(s):  
Sumio Iijima
Keyword(s):  
High Resolution ◽  
Electron Beam Irradiation ◽  
Fine Particles ◽  
High Resolution Electron Microscopy ◽  
Good Test ◽  
Resolution Electron ◽  
Single Crystal Films ◽  
Crystal Films ◽  
By Products ◽  
Test Objects

We have developed a technique to prepare thin single crystal films of graphite for use as supporting films for high resolution electron microscopy. As we showed elsewhere (1), these films are completely noiseless and therefore can be used in the observation of phase objects by CTEM, such as single atoms or molecules as a means for overcoming the difficulties because of the background noise which appears with amorphous carbon supporting films, even though they are prepared so as to be less than 20Å thick. Since the graphite films are thinned by reaction with WO3 crystals under electron beam irradiation in the microscope, some small crystallites of WC or WC2 are inevitably left on the films as by-products. These particles are usually found to be over 10-20Å diameter but very fine particles are also formed on the film and these can serve as good test objects for studying the image formation of phase objects.

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