Ancient Origins

Studies of the enzymes of glucan biosynthesis in plants show that the processes have very ancient origins. Thus key glucan biosynthetic enzymes are present even in the ancient algae. For example, plastidial starch biosynthesis appears to have evolved over 1,000 million years ago. The enzymes for starch biosynthesis first appeared in the cyanobacteria over 1,500 million years ago and their structures and functional roles have been preserved over the eons of time even into modern crop plants.