Enigmatic Isovaline: Investigating the Stability, Racemization, and Formation of a Non-biological Meteoritic Amino Acid

摘要: Among the Murchison meteoritic amino acids, isovaline stands out as being both nonbiological (non-protein) and having a relatively high abundance. While approximately equal amounts of D- L-isovaline have been reported in other CM meteorites, molecule's structure appears to prohibit its racemization aqueous solutions. We recently investigated low-temperature solid-phase chemistry valine with an eye toward each formation, stability, possible interconversions D L enantiomers. Ion-irradiated isovaline- valinecontaining ices were examined by IR spectroscopy highly-sensitive liquid chromatography/time-of-flight mass spectral methods assess acid destruction racemization. Samples studied presence absence water-ice, was measured function radiation dose. In addition, we undertaken experiments synthesize isovaline, valine, their isomers radiation-chemical pathways than oft-invoked Strecker process. This presentation will review summarize some our recent findings. -- Our work has supported grant Goddard Center for Astrobiology through NASA Institute. Experiments performed Cosmic Ice Laboratory (RLH, MHM, AL) Analytical (JPD, DPG) at Space Flight Center.