The four amino acids glutamic acid, phenylalanine, alanine and methionine were polymerized by heating to a temperature of 190-200 degrees C. Non-random polymers were obtained as evidenced by Edman degradation and FAB mass spectrometry analysis of cyanogen bromide fragments of the polyamino acid polymers. The polymers obtained from the thermal polymerization contained pyroglutamyl N-terminal groups, as evidenced by the lack of reaction with ninhydrin reagent.