Quantum chemical methods (X3LYP and MP2) were applied to investigate the structure and reactivity of anion-radical site in HZSM-5 zeolite. The interaction of hydrogen zeolite with a platinum particle can involve electron transfer to a Bronsted acid site to form an anion-radical fragment. A low stability of the latter favors the elimination of atomic hydrogen from the OH-group, an exothermic process with low activation energy. In the metal-zeolite catalysts, the anion-radical fragment formed due to withdrawal of electronic density from the metal particle can be responsible for the reverse spillover of Bronsted hydrogen onto the metal surface.