Cellulase refers to the hydrolysis of cellulose β-1,4-glucoside bond the cellulose into glucose a group of enzymes collectively, not a single enzyme, a multicomponent enzyme system but the act synergistically. Cellulase components are mostly glycoproteins, as a protein, the α- acids bonded via peptide bonds formed by natural organic polymer compound. Structure is very complicated, with many α- amino acid polypeptide chain to a certain order, between amino peptide chain is not directly connected by a special inter-molecular forces (hydrogen) binding, spiral, was superimposed spatial structure, which in state solution to the tertiary structure of the existence of a certain conformation, conformation and structure of this enzyme plays a catalytic function is necessary for a cohesive and flexible state. Closely depends primarily on hydrogen bonds within the protein, the solution of hydrogen bonds formed between water molecules and protein molecules to make hydrogen protein molecules within a certain degree of damage, protein structure becomes loose, showing an open state. Then enzyme molecules close and open two states in dynamic equilibrium, show some flexibility.

Large protein molecular weight, a particle size between 1 ~ 100nm. Because the volume of the protein molecule in the range of the volume of colloidal particles, the surface and a large number of hydrophilic groups, so that a solution having a colloidal nature, which can form colloids in water, become hydrophilic colloid. Because protein molecules hydrate film surface and surface charge, hydrophilic sol more stable. As different proteins with different molecular weight hydrophilic, higher the molecular weight, the smaller the hydrophilic, water-soluble protein having small molecules. Since cellulases are smaller molecules of protein, cellulose molecule polar hydrophilic group hydration with water, thereby cellulase will dissolve in water.

Many external factors influence protein solubility, which are: the solution pH, ionic strength, dielectric constant and temperature, but under certain ambient conditions of the same, different proteins have different solubilities. The cellulase in the product water pH deviates isoelectric point, the protein has a certain charge, will form the outer surface of the hydrated film, so that each molecule is not bonded to each other coagulation precipitation, and therefore have some solubility in water.

In addition, a small amount of salt can promote the dissolution of the protein, known as salt solubilization. In the aqueous protein solution (sol actually should be), was added a small amount of neutral salts, such as ammonium sulfate, sodium sulfate, sodium chloride, etc., will increase the surface charge of protein molecules, and the destruction of the electrical double layer of water molecules between the colloidal, enhance the role of the protein molecules and water molecules, so that the protein solubility in aqueous solutions increases.