Kex2 (kexin, E.C.3.4.212.61) is a Ca⁺²-dependent transmembrane protease found in the yeast Saccharomyces cerevisiae whose name derives from the killer expression phenotype of Kex2 mutant cells. Kex2 is the prototype of a large family of eukariotic pro-protein processing proteases that includes furin, PC2, PC3/PC1, PC4, PACE4, PC5/6 and PC7/LPC in mammals. What distinguishes the kex2 family of pro-protein convertases from subtilisin and its homologues is a high specificity for cleavage C-terminal to paired basic sites, most often KR or RR. Studies of values of kinetic constants are very much influenced by temperature. In this study we determined the individual rate constants (k₁:association constant; k_-1:dissociation constant; k₂ acylation constant and k₃:deacylation constant), and entropies, and activation energies in the kinetic mechanism of kex2 derived fom the temperature dependence of Michaelis-Mentem parameters kcat/Km and kcat, as well as the pKa1 and pKa2 of pH-profile, and the potassium effect  on the hydrolysis of FRET peptides Abz-YKREADQ-EDDnp and yours derivatives with modifications in the P' side. The informations gathered can provides additional insights into the energetic signatures of substrate recognition and hydrolysis. The application to Kex2 reveals how the various steps (association, dissociation, acylation and deacylation) of the catalytic mechanism and the pKa values and potassium effects are affected by differents FRET peptides.