Cathepsin H (CTSH) is a lysosomal cysteine protease belonging to the papain-like protease family. It plays a critical role in intracellular protein degradation, antigen processing, and extracellular matrix remodeling. CTSH is synthesized as an inactive proenzyme and activated upon exposure to acidic lysosomal environments. Unlike other cathepsins, CTSH retains a mini-chain post-activation, which influences its substrate specificity. It exhibits both endopeptidase and aminopeptidase activities, enabling diverse biological functions, including immune response regulation and tissue homeostasis.
CTSH antibodies are essential tools for studying its expression, localization, and function in physiological and pathological contexts. They are widely used in techniques like Western blotting, immunohistochemistry, and immunofluorescence to detect CTSH in cells, tissues, or biological fluids. Dysregulation of CTSH has been linked to diseases such as cancer, neurodegenerative disorders, and inflammatory conditions. For example, elevated CTSH levels are associated with tumor invasion and metastasis, while reduced activity is observed in neurodegenerative lysosomal storage diseases.
Research on CTSH antibodies also explores therapeutic potential, as inhibiting CTSH may mitigate pathological processes like cancer progression or inflammatory damage. However, its dual enzymatic roles complicate therapeutic targeting, necessitating precise antibody-based tools for functional studies. Recent studies highlight CTSH's role in COVID-19 pathogenesis, where it may facilitate viral entry by processing SARS-CoV-2 spike proteins. Overall, CTSH antibodies remain pivotal in unraveling its multifaceted biology and translational applications.