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

Table 4 Fragmentation pattern of the signal at m/z 599.2/598.2 obtained in the MS-spectrum of Se⁰-nanoparticle samples isolated from cultures of R. rubrum

Product ions (m/z)		Δ M (m. u.)	Signal intensity (% of base peak)
PPIX-O-CH₃ particle samples	m/z 599.2 particle samples	m/z 599 - PPIX-O-CH₃	PPIX-O-CH₃ particle samples	m/z 599.2 particle samples
531.3	553.2	22	9.8	5.5
517.3	539.2	22	72.6	85.6
504.3	525.2	21	100.0	100.0
490.3	511.2	21	19.3	28.3
473.3	495.2	22	9.4	5.1
459.3	481.2	22	20.2	6.4
445.3	466.2	21	39.6	20.9
431.3	452.2	21	27.5	10.4
417.3	438.2	21	10.2	6.4

The fragmentation pattern of the MS-Signal at m/z 599.2/598.2 (bold typing) was compared with that of PPIX-O-CH₃ (m/z 577.3) identified in the same particle samples (normal typing). Note that: 1) Each signal obtained in the MS/MS-spectrum of the analyte and of PPIX-O-CH₃ was for the same fragment loss, yielding a constant mass difference of 21 m. u. or 22 m. u. between each respective product ion of analyte and PPIX-O-CH₃. 2) This mass difference well agreed with the mass of Mg which was replaced by two or three protons. This result strongly suggested that the analyte corresponded to Mg-PPIX-O-CH₃

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