AMINO-ACID RACEMIZATION ON MARS - IMPLICATIONS FOR THE PRESERVATION OF BIOMOLECULES FROM AN EXTINCT MARTIAN BIOTA

Using kinetic data, we have estimated the racemization half-lives and times for total racemization of amino acids under conditions relevant to the surface of Mars. Amino acids from an extinct martian biota main tained in a dry, cold (<250 K) environment would not have racemized si gnificantly over the lifetime of the planet. Racemization would have t aken place in environments where liquid water was present even for tim e periods of only a few million years following biotic extinction. The best preservation of both amino acid homochirality and nucleic acid g enetic information associated with extinct martian life would be in th e polar regions. (C) 1995 Academic Press, Inc.