smaller Alb that is abundant in suspension. As a consequence, $C^S_A$ increases. Despite Alb lower affinity to the surface, its small size allows the protein to fit onto the free surface without experiencing strong repulsion with the Fib. Therefore, at this stage Alb and Fib are not necessarily competing between them, but are both competing with the IgG.

However, at larger time, when more Fib arrives to the surface, the competition is strong among all the three proteins. This induces the end of the re-adsorption of Alb and forces further conformational changes for the Fib (as in Fig.\[Fig1\]c). Our calculations support the identification of the third adsorption step, i.e. the end of the regime of constant Fib adsorption rate, with the end of the re-adsorption of Alb. This is more evident for the the lowest dilution, $X_P=100\%$, while is more speculative for the other values of $X_P$.

![Surface concentrations $C^S_i$ as function of time for $T=120$ K at (a) $X_P=100\%$, (b) $X_P=50\%$ and (c) $X_P=25\%$. At long time, $C^S_I>C^S_F$, with an inversion with respect to the standard conditions in Fig. \[f1\] where $C^S_F>C^S_I$. Errors and symbols are as in Fig. \[f1\]: Alb (), IgG (), Fib ($\Delta$) and their sum 