what is a zymogen
zymogen. an inactive precursor that is converted into an active enzyme by action of an acid or another enzyme or by other means; a proenzyme. zymogen cells. the secretory cells that secrete the zymogens.zymogen granules. contained in the cytoplasm of the secretory cells in the relevant gland.n inactive precursor that is converted into an active enzyme by action of an acid or another enzyme or by other means; a proenzyme. zymogen cells. the secretory cells that secrete the zymogens.