In chaperoning dithiothreitol denatured alpha -lactabumin, alpha -crystallin forms a chaperoning complex. In order to study the kinetics of such chaperoning it needs to be established whether the formation of the chaperoning complex is a reversible or irreversible process. The chaperoning reaction was studied by dynamic light scattering as a function of concentration and weight ratio of alpha -lactalbumin/alpha -crystallin. HPLC and subsequent SDS-PAGE gel electrophoresis experiments established that the chaperoning complex formed contains both alpha -crystallin and alpha -lactalbumin. Upon rechromatographing the chaperoning complex, the presence of monomeric alpha -lactalbumin has been demonstrated in addition to the chaperoning complex itself, This and equilibrium dialysis experiments demonstrated conclusively the existence of an equilibrium between monomeric partially denatured alpha -lactalbumin and the chaperoning complex made of alpha -lactalbumin and alpha -crystallin.