GZMK, as known as Granzyme K, is a member of a group of related serine proteases from the cytoplasmic granules of cytotoxic lymphocytes. Cytolytic T lymphocytes (CTL) and natural killer (NK) cells share the remarkable ability to recognize, bind, and lyse specific target cells. They are thought to protect their host by lysing cells bearing on their surface 'nonself' antigens, usually peptides or proteins resulting from infection by intracellular pathogens. The protein described here lacks consensus sequences for N-glycosylation present in other granzymes. Recombinant human GZMK, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.