Time course of global exchange of deuterium into apoBirA and its complexes with the four effectors shows protection from exchange. ApoBirA, □ BirA.biotin;x, BirA.btnSA, ▲, BirA.btnOH-AMP; ■, BirA.bio-5'-AMP; ◆. The continuous lines are the best-fit curves obtained from nonlinear least squares analysis of the data using a triple exponential model with Prism GraphPad.