CS229894B1 - Vasopressin analog and method of its production - Google Patents

Abstract

The invention relates to a vasopressin analogue of the chemical formula I i-------------------------------------- « Cys-D-Phe(Et)-Phe-Gln-Aan-Cys-Pro-Lya- -Gly-NH, 2 (I) where all chiral amino acids have the L configuration with the exception of p-ethylphenylalanine /Phe(Et)/, which has the D configuration. This analogue is characterized by having an inhibitory effect on the pressor activity of vasopressin. The essence of the method for producing a new vasopressin analogue consists in removing the protecting groups from the linear peptide of the formula II R2 R3 R4 r'-éys-D-Phe-Gln-Asn-Cys-Pro-Lya-Gly-NHg (Π) and the resulting disulfhydryl substance is oxidized to form a disulfide bond.

Description

The present invention provides a vasopressin analogue with an inhibitory action and a process for its preparation.

Analogs of neurohypophysic hormones that are able to inhibit the intrinsic activities of natural hormones may find application in medical practice.

It has been previously recognized (AO 226 923) that the introduction of a hydrophobic amino acid of configuration D at position 2 of oxytocin analogs results in oxytocin inhibitors. To date, the possibility of introducing an alkylated tyrosine of configuration D into position 2 of the vasoprealn molecule modified at positions 1 and 4 has been verified (Manning M., Olma A., Kile WA, Kolodzlejczyk A. 11., Seto J., Sawyer WH: J. Med Chem., 25, 45 (1982). It has now been found that even the mere substitution of the lysine-vesopressin molecule with D-p-ethyl-phenylalanine at the 2-position results in an analogue with an inhibitory effect on vesopressin activity in an in vivo rat test pAg = 7.05; pAg is the negative decadic logarithm of the analog concentration of Formula I, resulting in a decrease in the biological effect of vasopressin / blood pressure in a despinalized rat) to 50% of the original response.

(I) wherein all chiral amino acids have an L configuration except for p-ethylphenylAlenenenine (Phe (Bt)), which has my D configuration.

The process for producing the novel vasopressin analog of the formula I according to the invention is based on the preparation of a linear peptide of the formula II

(II) i2A removes the protecting groups R, R, ^RJ and R * and the resulting sulfhydryl compound ee oxidizes to form a disulfide bond.

The production method is further illustrated in the exemplary embodiment.

Example

The compound of formula II, the N-S-henzyloxykarbonyl benzylcysteinyl-DP-etylfenylelanin řenylalanyl-glutamyl-S-esparaginyl ^{benzyleysteinyl-prolyl-N6} -p-toluensulfonyllysyl-glycinamide (100 mg), prepared by stepwise construction of the solution was reduced with sodium in liquid ammonia (40 ml) until a blue color is obtained for 60 seconds. The color was then removed by the addition of acetic acid and the solution was lyophilized.

The residue was dissolved in 0.1 M HCl (10 mL), diluted to 200 mL with water, the pH was adjusted to 7, and after the addition of K ₃ Fe (CN) g solution until a permanent yellow color, this pH was maintained with stirring The solution was then loaded onto a carboxylate cation exchange column, the column was washed with 0.05% acetic acid and the product eluted with 50% acetic acid.

After lyophilization, the product was dissolved in water (10 ml) and loaded onto a column of modified octadecyl chain. (Column dimensions 50 x 0.9 cm). Loop was performed with a mixture of 40% methanol and 60% trifluoroacetic acid (0.1% free acid). Appropriate fractions were lyophilized. Product purity was verified by thin layer chromatography (4 systems), liquid chromatography and paper electrophoresis (2 buffers of different pH).

Amino Acid Analysis: Lys 1.07, Asp 1.03, Gln 0.92, Pro 0.94, Gly 1.04, Cys 1.84, Phe 1.06, Phe (Et) 0.92.

Claims (2)

SUBJECT OF THE INVENTION A vasopressin analog of formula I Cys-D-Phe (Et) -Phe-Gln-Asn-Cys-Pro-Lys-Gly-NH 4 wherein all chiral amino acids have the L configuration except for p-ethylphenylalanine (Phe (Et)), which has the D configuration. 2. A process for the preparation of a novel analog of vasopressin of formula (I) according to claim 1, characterized in that from a linear peptide of formula (II): H ² R ³ R ⁴ i III R'-Cya-D-Phe (Et) -Phe-Gln-Asn-Cys-Pro-Lys-Gly-NHg (II) 1 2 A removes the protecting groups R, R, Re Re The resulting disulfhydryl compound is oxidized to form a disulfide bond.