The paper determines the kinetic parameters of plasmins from eight species of mammals and their N-terminals. They were purified by the same methods (affinity chromatography and ion exchange) and activated with urokinase, starting from a common concentration and its kinetics judged according to Lineweaver-Burk coordinates. For such purpose, MichaelisMenten enzyme kinetics, which is widely used in the study of enzymes, was implemented. When compared with the molecular weight standard used, all plasminogen showed a purity exceeding 95% and a 92 kDa band on electrophoresis. Equine and canine plasmins showed the same KM due to the chromogenic substrate (0.438 mM), this being the one with the highest affinity in this study, and the human being the one with the lower affinity (5.3 mM). The catalytic constant and the conversion rate of the chromogenic substrate to product were also determined. The N-terminals of the plasminogens of the eight species were determined, and differences were found between humans and animals, as well as between some animals. Diferencias cineticas de las plasminas de ocho especies mamiferas: activaciones y secuencias de los terminales-N Omaira Canas Bermudez1 / Luis Fernando Arbelaez Ramirez2 1 MSc. Miembro del Grupo de Investigacion en Quimica, Departamento de Quimica, Facultad de Salud, Departamento de Medicina, Universidad de Pamplona, Pamplona, Colombia.  omairacbermudez@hotmail.com 2 PhD. Miembro del Grupo de Investigacion en Quimica, Departamento de Quimica, Facultad de Salud, Departamento de Medicina, Universidad de Pamplona, Pamplona, Colombia.  lui.ferar@hotmail.com Como citar este articulo: Canas Bermudez O, Arbelaez Ramirez LF. Diferencias cineticas de las plasminas de ocho especies mamiferas: activaciones y secuencias de los terminales-N. Rev Med Vet. 2013;(26):67-77.