175. Glycine peptides. Part I. The polymerization of piperazine-2 : 5-dione at 180°

An Evaluation of the Critical Parameters for Abiotic Peptide Synthesis in Submarine Hydrothermal Systems

“…The reverse reactions likely also occur. DKPs are formed in high yield by heating concentrated solutions of amino acids (Meggy 1953). Reaction of amino acids with DKP has been shown to produce short peptides (Nagayama et al 1990).…”

“…Amino acids can be oligomerized by heating in the dry state at 150°-180°C (Fox and Harada 1958), or in concentrated aqueous solution (9-18 M glycine anhydride) when heated at high temperature (180°C) for short periods of time (3-68 h) (Meggy 1953). Heating concentrated aqueous glycinamide (2 M final concentration at 80°C (Yanagawa et al 1984) or glycinamide (18 M) and ammonia (2-8 M) at 100°C also produces peptides (Oró and Guidry 1960).…”

The reaction kinetics of alanine and glycine under hydrothermal conditions

“…Diglycine and cyclic diglycine (2,5-diketopiperazine) have long been observed to polymerize and became a focus of early amino acid hydrothermal studies (Meggy, 1953;Meggy, 1956;Vallentyne, 1964). Vallentyne (1964) also noted that glycine produced various products including polymers, in contrast to alanine which in his study had only been observed to decarboxylate.…”

Some Early Historical Aspects of the Thermal Polycondensation of Amino Acids

“…Meggy (1953) studied the polycondensation of glycine, glycylg1ycine and diketopiperazine and found that the yield of po1yglycine was dependent on the heating time and the amount of water in the reaction system. In the case of the polymerization of diketopiperazine, the yield of polyglycine was the highest when the ratio of diketopiperazine to water was 2:1, prolonged heating decreased the polymer yield.…”