Biological activity of papain and papain-like (Cathepsin-K and cathepsin-B) enzymes as therapeutical modality candidates in degrading collagen in abnormal scar

Aims: This study aims to identify the potential of papain as a candidate for the treatment modality for abnormal scars via in silico studies. Methods: We determined the potential mechanism of the process of collagen degradation by papain by investigating its cleavage site-specificity and identifying human papain-like enzymes that have comparable biological activity in degrading collagen in the extracellular matrix using Merops, Bioedit, String DB and Cytoscape software. Results: Papain targets QQ_D (Glutamine-Glutamine Aspartic acid) motif for degradation while collagen only has QQ (Glutamine-Glutamine) motif. Additionally, the homology result showed that Cathepsin B has a closer relationship with papain compared with another candidate, Cathepsin K. Conclusion: Papain is a potential therapeutical modality candidate in degrading collagen in abnormal scars with an indirect mechanism as indicated by its cleavage site-specificity and its relationship with Cathepsin B, which degrades collagen via ubiquitin (UBC) proteasome.