Partial Purification and Characterization of Two Distinct Types of Caspases from Human Epidermis

The study isolated and characterized two distinct types of caspases from human epidermis, named F-I and F-II, with different molecular weights and substrate specificities. F-I, similar to caspase-3, had a molecular weight of 30 kDa and was involved in cleaving PARP during apoptosis. F-II, at 110 kDa, appeared to be a complex of multiple caspases with broader substrate specificity and unique inhibitor susceptibility, suggesting it was a novel caspase complex. Both caspases were implicated in epidermal apoptosis and keratinocyte differentiation, indicating their roles in the terminal differentiation processes of human keratinocytes. The study highlighted the complexity of epidermal apoptosis and its importance in forming a functional skin barrier.