0000000000133879
AUTHOR
Luca Ronda
More than a Confinement: “Soft” and “Hard” Enzyme Entrapment Modulates Biological Catalyst Function
Catalysis makes chemical and biochemical reactions kinetically accessible. From a technological point of view, organic, inorganic, and biochemical catalysis is relevant for several applications, from industrial synthesis to biomedical, material, and food sciences. A heterogeneous catalyst, i.e., a catalyst confined in a different phase with respect to the reagents’ phase, requires either its physical confinement in an immobilization matrix or its physical adsorption on a surface. In this review, we will focus on the immobilization of biological catalysts, i.e., enzymes, by comparing hard and soft immobilization matrices and their effect on the modulation of the catalysts’ function. Indeed, …
Immobilization of proteins in silica gel: Biochemical and biophysical properties
The development of silica-based sol-gel techniques compatible with the retention of protein structure and function started more than 20 years ago, mainly for the design of biotechnological devices or biomedical applications. Silica gels are optically transparent, exhibit good mechanical stability, are manufactured with different geometries, and are easily separated from the reaction media. Biomolecules encapsulated in silica gel normally retain their structural and functional properties, are stabilized with respect to chemical and physical insults, and can sometimes exhibit enhanced activity in comparison to the soluble form. This review briefly describes the chemistry of protein encapsulat…
Hemocyanin from E. californicum encapsulated in silica gels: oxygen binding and conformational states.
Cooperativity depends on the existence of equilibria among functionally distinct conformational states that are affected by homo and heterotropic effectors. In order to isolate the quaternary conformations of hemocyanin from E. californicum, the 24-meric giant protein was encapsulated in wet, nanoporous silica gels, either in the absence or presence of oxygen. The deoxy- and oxy-hemocyanin gels exhibit a p50 for oxygen of 11 and 2.5 torr, respectively, values in close agreement with those for hemocyanin in solution. The observed Hill coefficients are lower than unity, indicating a conformational heterogeneity within each locked conformational state, a finding in agreement with the assumptio…