Figure 3.

HDX kinetics for monomeric glucagon. HDX reactions were carried out for freshly prepared glucagon. Samples were withdrawn at various times (0.5–120 min) and analyzed using MS. Deuterium uptake was assessed for both intact glucagon and for proteolytic digests. (A) Deuterium uptake for intact glucagon as a function of time (0.5–120 min). Lines are fits to a monoexponential association function (Eq. 2) (n = 3). Standard deviations are less than the size of the symbols. The vertical dotted line indicates the half-life (t_1/2 = 5.3 min). (B) Percent deuterium uptake for nine pepsin digest fragments from glucagon as a function of time (0.5–30 min) (n = 3).