Table 2 Quantification of carbonyls and specific oxidation products of Met, Tyr, and Trp in G6PDH (54 μM) or 6PGDH (58 μM) exposed to 100 mM AAPH for 180 min at 37 °C.

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

 

MetSO

Di-Tyr

DOPA

Kyn

Carbonyls

G6PDH

Production (μM)

59.3 ± 16.2

0.03 ± 0.014

< 1.0

12.7 ± 3.9

7.6 ± 0.5

Per ROO·

0.04

2.1 × 10–5

–

8.8 × 10–3

5.3 × 10–3

Per protein

1.1

5.6 × 10–4

–

0.24

0.14

6PGDH

Production (μM)

69.6 ± 12.5

0.12 ± 0.016

< 1.0

16.2 ± 0.5

9.9 ± 2.5

Per ROO·

0.05

8.3 × 10–5

–

0.01

5.3 × 10–3

Per protein

1.2

2.1 × 10–3

–

0.28

0.17

  1. Total carbonyls were quantified by DNPH, while MetSO was determined in hydrolysed protein samples by HPLC with fluorescence detection and OPA precolumn derivatization. Di-tyrosine (Di-Tyr), 3,4-dihydroxyphenylalanine (DOPA) and kynurenine (Kyn) were assessed by LC–MS using selected reaction monitoring (SRM) with the following transitions: 198 → 151 for DOPA; 361 → 315 for di-Tyr; 209 → 94 for Kyn. Transitions corresponding to 237 → 118 for N-formylkynurenine, and 407 → 203 for di-tryptophan (di-Trp) were also followed, however, no signals were detected.
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