Rate of Hb Oxidation With and Without Removal of Adventitious Iron
| Experimental Condition . | n . | Hb Oxidation Rate (μmol/L/min) . | P . | |
|---|---|---|---|---|
| HbA . | HbS . | |||
| Hb at 1 mg/mL | ||||
| Hb | 6 | .028 ± .003 | .042 ± .004 | <10−4 |
| Hb + 10 μmol/L DTPA | 6 | .029 ± .004 | .035 ± .001 | .022 |
| dialyzed Hb | 3 | .030 ± .002 | .035 ± .002 | .042 |
| Hb at 100 mg/mL-150 | ||||
| Hb | 6 | .029 ± .003 | .042 ± .005 | .019 |
| Hb + 1 mmol/L DTPA | 6 | .028 ± .002 | .034 ± .002 | .002 |
| Experimental Condition . | n . | Hb Oxidation Rate (μmol/L/min) . | P . | |
|---|---|---|---|---|
| HbA . | HbS . | |||
| Hb at 1 mg/mL | ||||
| Hb | 6 | .028 ± .003 | .042 ± .004 | <10−4 |
| Hb + 10 μmol/L DTPA | 6 | .029 ± .004 | .035 ± .001 | .022 |
| dialyzed Hb | 3 | .030 ± .002 | .035 ± .002 | .042 |
| Hb at 100 mg/mL-150 | ||||
| Hb | 6 | .029 ± .003 | .042 ± .005 | .019 |
| Hb + 1 mmol/L DTPA | 6 | .028 ± .002 | .034 ± .002 | .002 |
Conditions were as follows: 140 mmol/L NaCl, 20 mmol/L HEPES, pH 7.0, [Hb] variable as indicated. Results are expressed as μmol/L heme oxidized per minute (mean ± SD). “Hb” refers to purified Hb prepared per Materials and Methods. “Hb + DTPA” indicates that experiment was conducted in presence of the indicated concentration of DTPA. “Dialyzed Hb” refers to purified Hb that was additionally treated with DTPA, followed by extensive dialysis against iron-free buffer to remove DTPA and any iron.
Results for samples at [Hb] >1 mg/L are expressed after dilution to [Hb] = 1 mg/mL, which allows rates to be directly compared.