Figure 3

GC-MS analysis of the enzymatic assays of the Mi EO with various substrates, viz, D-fructose-1,6-diphosphate (A-E), 3-buten-2-one (F-J) and 1-penten-3-one (K-O). The chromatograms represented are of the authentic standards of the expected products (A, F and K) and the assays of the protein expressed from the Mi EO (B, G and L) and the plasmid carrying reverse oriented insert (C, H and M) with the respective substrates (RI: reverse insert). For the assays with D-fructose-1,6-diphosphate, the chromatograms (A, B and C) represent trace of m/z 128 corresponding to the molecular ion of furaneol; whereas, for the assays with the other substrates, total ion chromatograms were monitored. The spectra represented are of the authentic standards of the expected products, viz, furaneol (D), butanone (I) and 3-pentanone (N) and of the peaks obtained in the Mi EO assays at the time corresponding to the expected products (E, J, O). The presence of m/z 70, 83 and 98 in (E) was because of the contaminating co-eluent which was also detected at the same time in (C).