PHOTOCHEMICAL PROCESSING OF AMINO-ACIDS IN EARTH ORBIT

Space technology in Earth orbit has been used to investigate whether a mino acids and peptides required for the emergence of life can be safe ly transported to Earth vicinity when they are associated with mineral s. In the BTOPAN-1 flight experiment, L-amino acids and one dipeptide were exposed to space conditions, free and associated with clays. Six amino acids found in the Murchison meteorite (Gly, Ala, Leu, Val, Asp, Glu) were tested with respect to chemical degradation and racemizatio n. In addition, photosensitive L-tyrosine was used to check possible o ligo tyrosine formation. The dipeptide L-alanyl-L-alanine was chosen t o test the stability of the peptide bond. No detectable traces of D-am ino acids could be found after the flight in any of the samples. Aspar tic acid and glutamic acid exposed as free samples have been partially decomposed during exposure to solar UV. Decomposition was prevented w hen the amino acids were embedded in montmorillonite or kaolinite. The other amino acids were unaffected by the flight. Tyrosine condense an d the dipeptide remained stable. (C) 1998 Elsevier Science Ltd. All ri ghts reserved.