Spin-dependent isotopic fractionation of L-methionine

Distinct isotopic fractionation in biomolecules, compared with atmospheric values, reflects their biosynthetic origin. Monitoring these fractionation changes offers a valuable approach for probing early metabolic networks. A key question in the study of life’s origins is the role of electronic spin and magnetic surfaces in symmetry breaking and the emergence of homochirality. Here, we used magnetic filters to show that the dynamical interaction with the magnetic surfaces changes the isotope fractions of ¹³C L-methionine compared with ¹²C L-methionine. Specifically, mass spectrometry analysis reveals that the isotopic fractionation of both natural and ¹³C-enriched L-methionine is influenced by electron spin-dependent interactions.