%0 Journal Article
%T Macromolecular Crowding Enhances Catalytic Efficiency and Stability of ¦Á-Amylase
%A Jay Kant Yadav
%J ISRN Biotechnology
%D 2013
%R 10.5402/2013/737805
%X In the present study an attempt was made to investigate the macromolecular crowding effect on functional attributes of ¦Á-amylase. High concentrations of sugar based cosolvents, (e.g., trehalose, sucrose, sorbitol, and glycerol) were used to mimic the macromolecular crowding environment (of cellular milieu) under in vitro conditions. To assess the effect of macromolecular crowding, the activity and structural properties of the enzyme were evaluated in the presence of different concentrations of the above cosolvents. Based on the results it is suggested that the macromolecular crowding significantly improves the catalytic efficiency of the enzyme with marginal change in the structure. Out of four cosolvents examined, trehalose was found to be the most effective in consistently enhancing thermal stability of the enzyme. Moreover, the relative effectiveness of the above cosolvents was found to be dependent on their concentration used. 1. Introduction Proteins are complex molecules and often unstable when they are placed out of their native environment. Proteins or enzymes may also lose their activity as a result of high temperature, aggregation, proteolysis, and suboptimal solution conditions. The purified proteins are often unstable and need to be stabilized in order to maintain the structural integrity and activity. Protein aggregation during processing and formulation is one of the major setbacks that limit the rapid commercialization of protein-based pharmaceuticals. Proteins aggregation is usually triggered by the formation of partially unfolded intermediates and therefore the demand for successful stabilization protocol is progressively increasing [1]. The phenomenon of stabilization of proteins infers the preservation of the native protein structure and activity during storage. The protein stabilization is based on the principle of limiting the molecular motion and conformational transition while maintaining the protein still in the native state [2, 3]. The native structure of a protein is dictated by various intramolecular interactions and its contacts with the surrounding solutes and solvents. Several sugars and polyols have extensively been used to stabilize the proteins against denaturation and to extend their shelf life during storage [4, 5]. The structural stability of a protein in an aqueous solution is determined by several types of weak interactions. The interactions between solvent, cosolvents, and protein have often been explained in terms of transfer free energy, preferential interaction parameters and preferential interaction
%U http://www.hindawi.com/journals/isrn.biotechnology/2013/737805/