aldolasa

Aldolasa refers to a group of enzymes that catalyze aldol cleavage or aldol addition reactions. These reactions are crucial in carbohydrate metabolism, particularly in glycolysis and gluconeogenesis. Aldolases are classified into two main types: Class I and Class II. Class I aldolases use a lysine residue in their active site to form a Schiff base intermediate with the carbonyl group of the substrate. This class is found in animals, plants, and fungi. Class II aldolases, on the other hand, utilize a metal ion, typically zinc, to activate the carbonyl group of the substrate. This type is prevalent in bacteria, yeast, and some algae. The aldolase reaction involves the cleavage of a carbon-carbon bond, often between the alpha and beta carbons of a sugar phosphate. For example, in glycolysis, fructose-1,6-bisphosphate aldolase cleaves fructose-1,6-bisphosphate into dihydroxyacetone phosphate and glyceraldehyde-3-phosphate. These enzymes play a vital role in breaking down sugars for energy production or in the synthesis of sugars during gluconeogenesis. Defects in aldolase enzymes can lead to various metabolic disorders.