Arachidonoyl Amino Acids and Arachidonoyl Peptides: Synthesis and Properties

V. V. Bezuglov ^a# , N. M. Gretskaya ^a , A. V. Blazhenova ^a , E. L. Andrianova ^a , M. G. Akimov ^a , M. Yu. Bobrov ^a , I. V. Nazimov ^a , M. A. Kisel’ ^b , O. L. Sharko ^b , A. V. Novikov ^c , N. V. Krasnov ^c , V. P. Shevchenko ^d , K. V. Shevchenko ^d , T. V. V'yunova ^d , and N. F. Myasoedov ^d
# Fax: +7 (095) 335-7103; e-mail: vvbez@oxylipin.ibch.ru
^a Shemyakin--Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , ul. Miklukho-Maklaya 16/10, Moscow , 117997 Russia
^b Institute of Bioorganic Chemistry , National Academy of Sciences of Belarus , ul. Zhodinskaya 5/2, Minsk , 220141 Belarus
^c Institute of Analytical Instrumentation, Russian Academy of Sciences, Rizhskii pr. 26, St . Petersburg, 198103 Russia
^d Institute of Molecular Genetics , Russian Academy of Sciences, pl. akademika Kurchatova 2, Moscow , 123182 Russia

Received August 16, 2005; in final form, September 19, 2005

Abstract: N-Arachidonoyl (AA) derivatives of amino acids (glycine, phenylalanine, proline, valine, γ-amino butyric acid (GABA), dihydroxyphenylalanine, tyrosine, tryptophan, and alanine) and peptides (Semax, MEHFPGP, and PGP) were synthesized in order to study the biological properties of acylamino acids. The mass spectra of all the compounds at atmospheric pressure electrospray ionization display the most intense peaks of protonated molecular ions; the detection limits for these compounds are 10 fmol per sample. AA-Gly showed the highest inhibitory activity toward fatty acid amide hydrolase from rat brain (IC₅₀ 6.5 μM) among all the acylamino acids studied. AA-Phe, AA-Tyr, and AA-GABA exhibited a weak but detectable inhibitory effect (IC₅₀ 55, 60, and 50 μM, respectively). The acylated amino acids themselves, except for AA-Glu, were stable to the hydrolysis by this enzyme. All the arachidonoylamino acids inhibited cabbage phospholipase D to various degrees; AA-GABA and AA-Phe proved to be the most active (IC₅₀ 20 and 27 μM, respectively). Attempts to detect the biosynthesis of AA-Tyr in homogenates of rat liver and nerve tissue in vitro were unsuccessful; however, AA-dopamine and AA-Phe, the products of its metabolism, were found. The highest contents of these metabolites were detected in liver homogenate and in the brain homogenate, respectively. Acylamino acids exert no cytotoxic effect toward the glioma C6 cells. It was shown that N-acylation of Semax with arachidonic acid results in enhancement of its hydrolytic stability and increases its affinity for the sites of specific binding in rat cerebellum membranes.

Key words: N-acylamino acids, N-acylpeptides, arachidonic acid, N-arachidonoyldopamine, electrospray mass spectrometry, fatty acid amide hydrolase, glioma C6, neurotoxicity, phospholipase D

Russian Journal of Bioorganic Chemistry 2006, 32 (3):231-239