Point de fusion des protéines - Etude de cas
De nombreuses protéines montrent de profonds changements lorsque leur milieu est modifié, le changement le plus radical étant la dénaturation thermique. Quand une protéine est chauffée au delà de son point caractéristique de stabilité thermique (point de fusion des protéines), un dépliement significatif peut conduire à exposer les chaines hydrophobes au milieu environnant (hydrophile) et à causer des agrégations sévères et irréversibles.
La diffusion de la lumière est idéale pour étudier le point de fusion des protéines, car la technique est extrêmement sensible aux grosses particules dispersées telles que les agrégats et les protéines dénaturées. Des changements similaires de la structure peuvent survenir au cours du temps, ou en fonction du pH, ou de la concentration en sel ou tout autre changement dans la solution. La diffusion dynamique (DLS) est une technique idéale pour évaluer rapidement la molécule en solution.
More information:
On demand presentation on Melting Point Protein Characterization. Proteins are charged biomolecules that can fold into compact structures that are very sensitive to solution conditions. As an extreme case, thermal denaturation can lead to irreversible loss of structure and function of the molecule. Thermal denaturation typically leads to an increase in size that can be monitored by dynamic light scattering. At the protein melting point, a marked increase in hydrodynamic size and scattering intensity is observed. This protein melting point temperature is indicative of the thermal stability of a protein. Modifications (such as glycosylation) can influence the stability and are easily observed using dynamic light scattering.
Application note on Melting Point Protein Characterization. Proteins are composed of polypeptide chains with unique 3-dimensional structures in the native state. These structures are stabilized by a combination of electrostatic and hydrophobic interactions, combined with a large degree of flexibility inside the structure of the molecule. If solution conditions change, denaturation or unfolding can quickly occur, along with a subsequent change in size. The sensitivity of dynamic light scattering is ideally suited for monitoring the stability of a protein to denaturing conditions. The protein melting point temperature is indicative of the thermal stability of a protein. Modifications (such as glycosylation) can influence the stability and are easily observed with dynamic light scattering.
Application note on a Therapeutic Protein Characterization. Proteins consist of polypeptide chains that are sensitive to various treatment conditions such as preparation, storage, buffer, etc. This application note describes dynamic and static light scattering characterization of a therapeutic antibody supplied in two forms: an untreated and a treated preparation. Information about the treatment process was not divulged. Hydrodynamic size, molecular weight and melting point of the two samples are compared. The absence of a melting point in the treated sample seems to suggest that the treatment process was similar in effect to thermal denaturation.
Enregistrement gratuit
Access application notes, webinars, videos and more.
Enregistrez-vous maintenant
