The shape and chemical properties of the substrate and the active site of the enzyme have the greatest effect on the ability of a substrate to bind to an enzyme. The active site is a specifically shaped pocket or crevice on the surface of the enzyme where the substrate binds, and the shape and chemical properties of the active site are complementary to those of the substrate. The binding of the substrate to the active site involves various types of chemical interactions, including hydrogen bonds, electrostatic interactions, and van der Waals forces. The degree to which the substrate can interact with the active site depends on factors such as the size, shape, charge distribution, and functional groups of the substrate and the active site. If the substrate and active site are not complementary, the substrate may not be able to bind effectively, resulting in a lower reaction rate or no reaction at all.