Research up to this point had shown that NAD was important for fermentation in yeast and health in humans and animals. It had uncovered various ways in which NAD was generated in the cell. Although quite a bit was known about the ways that the NAD molecule was “built” in the cell, no research up until this point had shown a chemical reaction in which the NAD molecule was taken apart, or broken down into its component parts. Mandel’s work identified a reaction that broke NAD into two parts, nicotinamide and ADPribose.