In a cyclic voltammetry experiment carried out with an adsorbed redox protein, the oxidation and reduction of each redox site shows as a pair of positive and negative peaks. Since all the sample is oxidised or reduced during the potential sweep, the peak current and peak area should be proportional to scan rate (observing that the peak current is proportional to scan rate proves that the redox species that gives the peak is actually immobilised). The same is true for experiments performed with non-biological redox molecules adsorbed onto electrodes. The theory was mainly developed by the French electrochemist Etienne Laviron in the 1980s.
Since both this faradaic current (which results from the oxidation/reduction of the adsorbed molecule) and the capacitive current (which results from electrode charging) increase in proportion to scan rate, the peaks should remain visible when the scan rate is increased.  In contrast, when the redox analyte is in solution and diffuses to/from the electrode, the peak current is proportional to the square root of the scan rate (see: Randles–Sevcik equation).