Figure 4 | Scientific Reports

Figure 4

From: Implications of differential peroxyl radical-induced inactivation of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase for the pentose phosphate pathway

Figure 4

Quantification of His, Tyr, Trp, and Met modification and formation of methionine sulfoxide (MetSO) in samples of G6PDH (panel A) and 6PGDH (panel B) treated with 10 (blue) and 100 (orange) mM AAPH. G6PDH (54 μM monomer) and 6PGDH (58 μM monomer) were incubated with AAPH at 37 °C in 75 mM phosphate buffer at pH 7.4 for 180 min. Aliquots were then taken, AAPH removed, and amino acid content assessed by OPA derivatization and HPLC analysis, as described in the Material and methods. Results were normalized to the concentration of Leu residues (to compensate for any losses during processing), and are expressed as moles of residue per mole of protein. The white bars show data determined at time zero. Incubations for 180 min of proteins in the absence of AAPH showed minor changes in amino acid content (data not shown). Data correspond to means ± standard deviations of at least three independent hydrolyses, from three independent experiments. Statistical differences are indicated as follows: *p < 0.05, **p < 0.01, and ****p < 0.0001.

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