In cotyledons, what is the enzyme that breaks down the starch called and what is its optimum pH?
The enzyme in plants which breaks down starch is sometimes called Diastase. It is actually alpha-amylase and beta-amylase enzymes. Alpha-amylase hydrolyses starch internally to yield long chains of alpha-1-4-glucose. Beta-amylase hydrolyses these chains from the ends to produce maltose. Maltase then converts the maltose to glucose for use in the plant. The optimum pH is usually found to be on the alkaline side of neutral, but the precise value does depend on the source of the amylases.
