Reply to Bada: The relevance of meteoritic alpha-methyl amino acids to prebiotic homochirality

Abstract

In his letter Bada (1) is complimentary with respect to the work we actually performed and reported in a recent issue of PNAS (2). However, he is skeptical about the relevance of the alpha-methyl amino acids found by others in the Murchison meteorite, species with a few percent of an excess of the L enantiomers. He states that the amount delivered would not be “sufficient,” although he does not produce or justify any estimate of how much would be enough to produce water solutions in which life could start. He does offer an estimate of what concentration one would have if such a meteorite fell into a lake the size of Lake Mead, but that is much less probable than that the meteorite would land on earth, as did the Murchison and Murray meteorites in recent times.