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Search for New Synthetic Immunosuppressants. Antamanide Analogues Containing the Tetrazole Ring as a cis-Peptide Bond Mimetic

100%

Zubrzak P. , Kaczmarek K. , Kowalski M. L. , Szkudlińska B. , Zabrocki J.

Polish Journal of Chemistry

2001

tom Vol. 75, nr 12

1869-1876

Linear and cyclic antamanide (ANT) analogues with dipeptide segments Pro2-Pro3, Pro7-Pro8 and both of them replaced by their tetrazole analogue Pro-psi[CN4]-Ala, respectively, have been synthesized by SPPS method and cyclization with TBTU reagent. The peptides were examined for their immunosuppressive activity in a lymphocyte proliferation test (LPT).

A novel cis-peptide bond motif inducing β-turn type VI. The synthesis of enkephalin analogues modified with 4-aminopyroglutamic acid.

100%

Kaczmarek K. , Kaleta M. , Chung N. N. , Schiller P. W. , Zabrocki J.

Acta Biochimica Polonica

2001

tom 48

nr 4

1159-1163

A new pathway leading to a mixture of four isomers of 4-aminopyroglutamic acid is described. Michael type addition of Z-ΔAla-OMe to enolates prepared from acylaminomalonates, followed by hydrolysis and decarboxylation give protected 4-aminopyroglutamic acid with the 4-aminopyroglutamic acid with the cis:trans ratio approximately 3:2. This mixture was incorporated into Leu-enkephalin (position 2-3). After separation of peptides it appeared that all analogues were essentially inactive in guinea pig ileum and mouse vas deferens bioassays.

Stereochemistry of insect kinin tetrazole analogues and their diuretic activity in crickets.

88%

Nachman R. J. , Coast G. M. , Kaczmarek K. , Williams H. J. , Zabrocki J.

Acta Biochimica Polonica

2004

tom 51

nr 1

121-127

Insect kinin analogues of the sequence Phe-Phe-ψ[CN4]-Ala-Trp-Gly-NH2 containing (L-Phe2,L-Ala3) and (L-Phe2,D-Ala3) stereochemical variants of the tetrazole moiety, a mimic of the type VI β-turn, demonstrate significant agonist and partial antagonist activity, respectively, in a cricket diuretic bioassay. A comparison of the solution conformations of these two stereochemical variants indicates a structural basis for their divergent bioactivities. The (D-Phe2,D-Ala3) stereochemical variant was synthesized and found to demonstrate significant agonist activity. The results further define stereochemical requirements for the diuretic activity of insect kinins in crickets and provide valuable information for the design of biostable analogues capable of disrupting digestive and diuretic processes in pest insects.

Stereochemistry of insect kinin tetrazole analogues and their diuretic activity in crickets

75%

Nachman R. J. , Coast G. M. , Kaczmarek K. , Wiliams H. J. , Zabrocki J.

Acta Biochimica Polonica

2004

tom 51

nr 1

Insect kinin analogues of the sequence Phe-Phe-Ψ[CN4]-Ala-Trp-Gly-NH2 containing (L-Phe2,L-Ala3) and (L-Phe2,D-Ala3) stereochemical variants of the tetrazole moiety, a mimic of the type VI -turn, demonstrate significant agonist and partial antagonist activity, respectively, in a cricket diuretic bioassay. A comparison of the solution conformations of these two stereochemical variants indicates a structural basis for their divergent bioactivities. The (D-Phe2,D-Ala3) stereochemical variant was synthesized and found to demonstrate significant agonist activity. The results further define stereochemical requirements for the diuretic activity of insect kinins in crickets and provide valuable information for the design of biostable analogues capable of disrupting digestive and diuretic processes in pest insects.