GZMH also known as Granzyme H is essential for HBV eradication. The HBx protein (HBx), required for the replication of HBV, is cleaved at Met(79) by GZMH. GZMH inhibitor can abolish GZNH- and lymphokine-activated killer cell-mediated HBx degradation and HBV clearance. An HBx-deficient HBV is resistant to GzmH- and lymphokine-activated killer cell-mediated viral clearance. Recombinant human GZMH, fused to His-tag at N-terminus, was expressed in E.coli.