Fig. 2. Formation of NAAs in the Gly + POPC reaction. (A) TLC analysis of Gly (G) + POPC (P) reaction mixture, which was subjected to five wet–dry cycles at 90 °C. A new band is observed in lane 4, which is absent in other control reactions (lanes 1–3), indicating the formation of a new product upon wet–dry cycling in the Gly + POPC reaction. R_f values for the POPC and the new product are 0.31 and 0.38 respectively. Bands were visualized by staining with the fluorescent dye primuline, whose fluorescence increases in the presence of molecules containing long hydrocarbon chains. (B) HRMS analysis (negative ion mode) of the butanol phase collected during BH extraction of the above-mentioned reaction shows two predominant peaks with masses corresponding to NAAs namely, NPG ([M − H]⁻ = 312.2529) and NOG ([M − H]⁻ = 338.2697). (C) An overview of the reactions occurring in the Gly + POPC mixture, under wet–dry cycles. Gly can either react with another Gly molecule to form diglycine or it can react with POPC to generate NAAs (NPG and NOG). Diglycine may undergo further elongation to form higher oligomers or cyclize to form DKP.