Unveiling of natural hidden activity based on mechanism similarity.

The finding a suitable substrate based on mechanism similarity is a useful tool for discovering hidden native activity from known enzyme. Aldolases and 4-epimerases are potent industrial biocatalysts used for transforming stereoisomers of carbohydrates. They shares a mechanism for cleaving the C3−C4 bond in sugar phosphate, despite of different class enzymes. The novel 4-epimerase activity of fructose-1,6-biophosphate aldolase (FbaA) was discovered by finding a suitable substrate, fructose-6-phosphate, for epimerase activity through molecular docking. FbaA, therefore, is a dual function enzyme using different active sites within the same pocket that acts both 4-epimerase and aldolase. The 4-epimerase activity has been concealed due to the fast metabolic flux of glycolysis.