Table 2. Quantitative Measures of Deuterium Uptake in Mb Formulations.
| peak
width (Da) |
||||||
|---|---|---|---|---|---|---|
| formulationa | deuterium uptake (%)b,c | Nfastb,d | Nslowb,d | Nfast/(Nfast + Nslow) | ∼15% deuterationb,e | ∼12.5% deuterationb,e |
| MbA | 9.4 ± 0.1 | 19.6 ± 0.9 | 6.3 ± 0.4 | 0.76 ± 0.04 | 17.2 ± 0.3 | 15.4 ± 0.3 |
| MbB | 24.6 ± 0.2 | 39.8 ± 1.6 | 19.7 ± 1.4 | 0.67 ± 0.04 | 18.4 ± 0.1 | 15.8 ± 0.3 |
| MbC | 35.8 ± 0.2 | 36.0 ± 1.4 | 37.9 ± 1.1 | 0.49 ± 0.02 | 33.6 ± 1.1 | |
| MbD | 32.7 ± 0.2 | 34.8 ± 0.9 | 32.7 ± 0.6 | 0.52 ± 0.01 | 31.1 ± 0.5 | |
| MbE | 8.4 ± 0.1 | 14.6 ± 0.5 | 4.4 ± 0.3 | 0.77 ± 0.06 | 14.8 ± 0.2 | |
a
See Table 1 for the composition.
b
Values obtained from three independent ssHDX-MS experiments (mean ± SE).
c
Percent deuterium uptake relative to theoretical maximum by intact Mb after 48 h of HDX at 5 °C, 33% RH.
d
Nfast and Nslow values were determined by nonlinear regression of ssHDX-MS kinetic data. Time course of deuterium exchange for intact Mb was fitted to the two phase exponential association model (eq 1).
e
Peak width was measured at 20% height of the deconvoluted mass spectrum of intact Mb.