Manganese is a component of some enzymes and stimulates the development and activity of other enzymes.  Manganese superoxide dismutase (MnSOD) is the principal antioxidant in mitochondria.  Several enzymes activated by manganese contribute to the metabolism of carbohydrates, amino acids, and cholesterol.
A deficiency of manganese causes skeletal deformation in animals and inhibits the production of collagen in wound healing.