Human Cystatin D Biotinylated Antibody

Cystatin D is a member of family 2 of the cystatin superfamily (1). In contrast to other members of family 2, Cystatin D has restricted tissue distribution and has been found only in saliva and tears. Two allelic variants (Arg46 and Cys46) are known in the human protein and they are not significantly different in their inhibitory activity against papain and cathepsins B, H, L and S (2). The functions of Cystatin D are largely unknown. However, Cystatin D has been shown to inhibit coronavirus replication at its physiological concentration (0.12‑1.9 μM) and has been suggested to play a protective role against proteases present in the oral cavity (3).