Not available – first paragraph follows: Isozymes are multiple molecular forms of an enzyme derived from a tissue of an organism. They are usually separated when an electric charge causes their migration through a gel, and they are visualized when the gel is placed in a solution of the proper substrate for the enzyme and the end product of the reaction is stained. This procedure results in discrete bands, whose positions in the gel are determined by the charge and molecular weight of the isozymes. The preparation is usually a simple extract, sometimes just the unmodified juice obtained by crushing the plant sample.