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Table 2 Demetalation experiments

From: Inhibition of bacteriochlorophyll biosynthesis in the purple phototrophic bacteria Rhodospirillumrubrum and Rhodobacter capsulatus grown in the presence of a toxic concentration of selenite

Samples Initial mass (m/z) Final mass (m/z) Decrease of initial mass (m. u.) σ(%)
Reference BChl ap 910.5 888.6 21.9 9.3
Reference Bchlide a 632.3 610.3 22 2.3
Particle sample extracts R. rubrum 905.5 882.6 21.9 **
Particle sample extracts R. rubrum 632.3 610.3 22.0 4.5
Particle sample extracts Rba. capsulatus 616.2 616.2 93.5
Particle sample extracts Rba. capsulatus 595.3 595.3 91.6
  1. Signal intensities were measured before (Initial mass) and after treatment (Final mass) of reference molecules or particle sample extracts with conc. acetic acid (see “Methods section”). σ represents the final signal intensity of the metalated compound expressed in % of its initial intensity (see text).
  2. **A signal of high intensity was obtained at m/z 882.6 in the MS-spectrum of this particle sample extract already before addition of concentrated acetic acid. This may indicate that Bchl ag was largely demetalated during the extraction process (Additional file 6) and, most likely, that BPhe ag was more efficiently detected in the particle sample extracts than in the native particle samples. Consequently, demetalation was difficult to quantify for this molecule