Calcium guanylate is the calcium salt of guanylic acid also known as GMP. It is a nucleotide composed of guanine, ribose, and one phosphate group formed during protein synthesis. It is an ester of phosphoric acid with the nucleoside guanosine. Commercially it is produced from dried fish, yeast extract, or dried seaweed. It produces an odourless, colourless or white crystal or crystalline power that is slightly soluble in water and is used as a flavour enhancer in food.http://www.creative-enzymes.com/product/Calcium-Guanylate_481.html