Citation

Cushman M, Chinnasamy P, Chakraborti AK, Jurayj J, Geahlen RL, Haugwitz RD. Int. J. Pept. Protein Res. 1990; 36(6): 538-543.

Copyright

(Copyright © 1990, John Wiley and Sons)

DOI

10.1111/j.1399-3011.1990.tb00993.x

PMID

2090646

Abstract

An asymmetric synthesis of [beta-(4-pyridyl-1-oxide)-L-alanine4]-angiotensin I (1a), which is a potential suicide substrate (mechanism-based inhibitor) for protein-tyrosine kinases, has been performed. Deprotonation of 6 with n-butyllithium in THF gave the anion 7, which was alkylated with 4-(chloromethyl)pyridine-1-oxide to afford intermediate 9 as a crystalline solid. Hydrolysis of 9 afforded a mixture of 11 and 12 in a ratio of 96:4 as estimated by conversion to the diastereomeric dipeptides 13 and 14 followed by HPLC analysis. The 96:4 mixture of 11 and 12 was used in the solid phase synthesis of the target angiotensin analog 1a and its diastereomer 1b, which were separated and tested for inhibitory activity against two thymocyte protein-tyrosine kinases: p40 and p56lck. Neither peptide displayed significant inhibitory activity toward p40 and both served as weak competitive inhibitors of p56lck.

Language: en

Keywords

Angiotensin I; Protein-Tyrosine Kinases