Racemization of Acylated Amino Acids

Racemization of Meteoritic Amino Acids

Meteorites may have contributed amino acids to the prebiotic Earth, affecting the global ratio of right-handed to left-handed (D/ L) molecules. We calculate D/ L ratios for seven biological, α-hydrogen, protein amino acids over a variety of plausible parent body thermal histories, based on meteorite evidence and asteroid modeling. We show that amino acids in meteorites do not necessarily underg...

Racemization of amino acids in marine sediments.

Isoleucine, one of several amino acids isolated from a suite of welldated deep-sea cores, shows a progressive increase in the degree of racemization with the age of the sediment. Amino acids in sediments show an initial rate of racemization almost an order of magnitude faster than the rate observed for free amino acids at a comparable pH and temperature. The observed kinetics depend on a variet...

Correction: Abiotic Racemization Kinetics of Amino Acids in Marine Sediments

The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and a...

Amino Acid Racemization

The Racemization of Amino Acids in Aqueous Solution by Acetic Anhydride

In a previous investigation du Vigneaud and Sealock (1) have reported that the sodium salt of acetyl-l-tryptophane in aqueous solution at 35-40” is completely racemized by acetic anhydride within a few hours. The ease of racemization and particularly the mild conditions under which the reaction occurred seemed to us to offer an excellent method for racemizing amino acids if the reaction should ...