LYSINONORLEUCINE . A NEW AMINO ACID FROM HYDROLYSATES OF ELASTIN

This paper describes the characterization and synthesis of a new amino acid isolated from hydrolysates of elastin. Results from dinitrophenylation studies, nuclear magnetic resonance spectra, infrared spectra, and mass spectra suggest that the structure is Nϵ-(5-amino-5-carboxypentyl)lysine. To this compound we have assigned the trivial name lysinonorleucine. Synthesis can be achieved via two different procedures : (1) Nα-acetyllysine is oxidized by N-bromosuccinimide to α-acetylaminoadipic acid δ-semialdehyde, which is then condensed with Nα-acetyllysine to a Schiff base. The Schiff base is reduced with sodium borohydride and the resulting product is hydrolyzed by acid to lysinonorleucine (5-10% yield); (2) 1 equiv of 5-(δ-bromobutyl)hydantoin is condensed with 1 equiv of Nα-benzoyllysine ethyl ester by refluxing in tetrahydrofuran. The condensate is then treated with alkali at elevated temperature to yield lysinonorleucine (57% yield). Treatment of the naturally occurring amino acid with snake venom L-amino acid oxidase indicated that both L-carbons are in the L configuration. © 1969, American Chemical Society. All rights reserved.