Asunto(s)
Resinas de Intercambio Iónico/metabolismo , Sodio/metabolismo , Succinatos/metabolismo , Animales , Edema/etiología , Edema/terapia , Femenino , Técnicas In Vitro , Intercambio Iónico , Resinas de Intercambio Iónico/efectos adversos , Resinas de Intercambio Iónico/uso terapéutico , Enfermedades Renales/metabolismo , Enfermedades Renales/fisiopatología , Potasio/metabolismo , Ratas , Ratas Endogámicas , Succinatos/efectos adversos , Succinatos/uso terapéuticoRESUMEN
A kinetic mechanism for the digestion of collagen by bacterial collagenase has been proposed which is consistent with experimental data. Arguments are presented justifying the application of a homogeneous approach to the digestion of insoluble collagen. The mechanism takes account of increased kinetic blockages with aging and enzyme complexity. It is shown to be applicable to collagen from various tissues, including relatively impure preparations. However, the mechanism is not applicable to collagen from the immature period of the lifespan. Kinetic blockages are shown to increase three- to four-fold from age 20 to 70 years, within the main helical region of the collagen molecule. There is no increase of kinetic blockages in the N-terminal region of the molecule over this age range.
Asunto(s)
Envejecimiento , Colágeno/metabolismo , Modelos Biológicos , Adulto , Anciano , Sitios de Unión , Digestión , Humanos , Cinética , Colagenasa Microbiana/metabolismo , Persona de Mediana Edad , Conformación ProteicaRESUMEN
The digestion of human collagen by bacterial collagenase was studied in order to relate collagen structure to the digestion kinetics. The digestion was shown to be first order in collagen and in collagenase on given material from run to run. There was no product inhibition and no enzyme deactivation. However, the rate changed with age, and also within a run as a function of conversion. It was shown that the normalized time (time X enzyme concentration), to reach a given amount of digestion can be plotted as a linear function of the sample age, from 20 to 70 years. The digestion broke down into two regions. The first was a rapid first order region which amounted to about 10% of the collagen. The second region could be graphed as a second order plot to obtain a straight line. This implied that the rate of digestion was functionally second order in collagen; first order in concentration and first order in conversion of collagen.