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. 2014 Mar;196(5):1055–1063. doi: 10.1128/JB.01230-13

FIG 4.

FIG 4

ESI-MS analysis of metabolites of the phosphomevalonate decarboxylase reaction. All spectra were collected in the negative ion mode. (A) MS spectrum of chemically synthesized (R,S)-mevalonate 5-phosphate (m/z = 227). (B) MS spectrum of chemically synthesized isopentenyl 5-phosphate (m/z = 165). (C) MS spectrum of a PMD reaction mixture indicating residual unreacted (S)-mevalonate 5-phosphate (m/z = 227) and showing product isopentenyl 5-phosphate (m/z = 165). (D) MS spectrum of negative control in which no enzyme was included in the reaction mixture. Unreacted (R,S)-mevalonate 5-phosphate substrate is apparent (m/z = 227), but no formation of a product (m/z = 165) peak is observed. (E) MS-MS spectrum of an m/z of 165, yielding phosphate ions (m/z = 79 and m/z = 97).