Reassessing enzyme kinetics: considering protease-as-substrate interactions in proteolytic networks.
Proteases are enzymes that degrade proteins and play a major role in cellular homeostasis. One such class, cysteine cathepsins, contain the most powerful mammalian collagenase and elastase. When studied in combination, there are protease-on-protease interactions, cathepsin cannibalism interactions, that ultimately reduce the pool of active protease in a system. Cysteine cathepsins are lysosomal proteases involved in extracellular matrix remodeling and are often found upregulated in tissue destructive diseases such as cancer, osteoporosis, atherosclerosis, rheumatoid arthritis, and tendinopathy.