Sandra Pizzarello

Sandra Pizzarello's research over the last forty years involved the analysis of organic compounds in several carbonaceous chondrites, particularly molecular, chiral, and isotopic characterization of amino acids. Because the formation of these organic-rich meteorites pre-date the origin of life, they had been under investigation as potential sites of primal organic compounds which could shed light on abiogenesis, specifically the origin of biological homochirality.^[3] Such studies, however, had been inconclusive until 1997 when Cronin and Pizzarello detected 7-9% L-enantiomeric excesses of three abiological amino acids while analyzing the Murchison meteorite.^[3]

Given Earth's history of meteoric impacts and the observation that meteors contain an excess of the biologically relevant L-stereoisomer of certain amino acids, Pizzarello studied the effect of meteoritic amino acids in enantiomeric excess on the formation of other biological molecules.^[4] In one study, Pizzarello found that nonracemic solutions of abiological isovaline and proteinogenic alanine can direct the condensation of glycolaldehyde to produce nonracemic solutions of threose and erythrose via an aldol reaction concluding that amino acids can act as asymmetric catalysts in carbohydrate synthesis.^[4] These findings support the origin of life hypothesis that homochirality originated prior to life and from extraterrestrial origins.^[4] However, Pizzarello's theoretical inquiries into cosmochemical evolution remain debated based on suspect analytical evidence of meteoritic enantiomeric excesses.^[5][6][7]

1. # https://nai.nasa.gov/directory/pizzarello-sandra/ NASA.gov
2. https://webapp4.asu.edu/directory/person/274781