Now in addition to that serene, as we'll see in the next lecture, there are other additional residues present in the active side that also assist in the catalysis process as we'll discuss in the next lecture. Now, what are some examples of senior proteases and what are some of their roles? So let's begin with some digestive enzymes. So we have trypsin, we have chimetrypsin, we also have elastase. And these three are digestive enzymes found inside our small intestine which basically play the role of breaking down the proteins that we ingest. We also have cum proteases involved in the blood coagulation process and we'll discuss these in much more detail when we'll discuss the blood cascade.