This procedure can distinguish between the 60 different varieties of rootstock by comparing the patterns developed after electrophoresis separation of specific enzymes active in prepared cambial tissue samples.
Enzymes are the largest and most highly specialized class of protein molecules.
They are the primary means for the expression of gene action due to their unique ability to catalyze the multitude of biochemical reactions constantly occurring in all living systems. Over a thousand different enzymes have been identified and isolated in pure form, and a number of these have actually been prepared as pure protein crystals indicating a high degree of organization and order. In this instance, the grapevine rootstock DNA present in different varieties codes for the expression of subtly different forms of the same enzyme. These forms differ slightly in the way in which they are folded, in the nature and type of surface charges, and in their response to gradations in pH during electrophoresis. Electrophoresis is a method of separating the different forms of enzymes present in plant tissue samples.