WHILE MUCH OF THE MANNOSE USED IN GLYCOSYLATION IS BELIEVED TO BE DERIVED FROM GLUCOSE, IN CULTURED HEPATOMA CELLS (CANCEROUS CELLS FROM THE LIVER), MOST OF THE MANNOSE FOR GLYCOPROTEIN BIOSYNTHESIS COMES FROM EXTRACELLULAR MANNOSE, NOT GLUCOSE. MANY OF THE GLYCOPROTEINS PRODUCED IN THE LIVER ARE SECRETED INTO THE BLOODSTREAM, SO DIETARY MANNOSE IS DISTRIBUTED THROUGHOUT THE BODY.
MANNOSE IS PRESENT IN NUMEROUS GLYCOCONJUGATES INCLUDING N-LINKED GLYCOSYLATION OF PROTEINS. C-MANNOSYLATION IS ALSO ABUNDANT AND CAN BE FOUND IN COLLAGEN-LIKE REGIONS. SEVERAL CONGENITAL DISORDERS OF GLYCOSYLATION ARE ASSOCIATED WITH MUTATIONS IN ENZYMES INVOLVED IN MANNOSE METABOLISM.
IT IS SEEN TO BE EFFECTIVE IN URINARY TRACT INFECTION.