Adhesion is the attraction between two or more polarized molecules that are not alike. A catalyst is a substance that affects the rate of a chemical reaction but is not consumed during the reaction. The amount of a catalyst present at the end of a reaction should be same as was present at the beginning of the reaction. An enzyme is a catalyst composed of protein. Many catalysts, such as platinum, are not composed of protein.
Proteins have many uses in cells, such as being used as a structural material to build cell parts.