reversible phosphorylation

…in the mid-1950s while studying reversible phosphorylation—i.e., the attachment or detachment of phosphate groups to cell proteins. The two men were the first to purify and characterize one of the enzymes (phosphorylase) involved in the process of phosphorylation. They also discovered the enzymes that catalyze the attachment and detachment of…

They discovered reversible protein phosphorylation, a biochemical process that regulates the activities of proteins in cells and thus governs countless processes that are necessary for life.