SYNTHESIS AND BIOLOGICAL EVALUATION OF AN N-6-DIETHYLPHOSPHOLYSYL PEPTIDE - A MODEL-COMPOUND WITH A COVALENTLY ATTACHED METABOLITE OF AN ORGANOPHOSPHATE PESTICIDE

A model peptide containing N-6-diethylphospholysine on an internal pos ition, Ac-Ala-Lys(PO(3)Et(2))-Val-OEt, and two nonphosphorylated pepti des, Ac-Ala-Lys-Val-OEt and Ac-Tyr-Lys-Val-OEt, were synthesized in hi gh yields and fully characterized by physicochemical constants, HPLC, and NMR and mass spectra. A rat growth study was conducted to determin e bioavailability of lysine in the three peptides. A wheat gluten (20% ) basal diet, adequate in all nutrients except lysine (0.26%), was sup plemented with 0.1% crystalline lysine. Lysine bioavailability was cal culated by comparing growth of rats fed the peptide diets with that of rats fed basal plus 0.1% crystalline lysine diet. Values for bioavail ability of lysine in Ac-Ala-Lys(PO(3)Et(2))-Val-OEt, Ac-Ala-Lys-Val-OE t, and Ac-Tyr-Lys-Val-OEt were 0, 79, and 95%, respectively.