Trypsin, Chymotrypsin & Elastases -What type of enzymes are they?
**Core Concept**
Trypsin, chymotrypsin, and elastases are serine proteases that belong to the class of enzymes known as peptidases. These enzymes are crucial for the digestion of proteins in the gastrointestinal tract.
**Why the Correct Answer is Right**
These enzymes are serine proteases that use a serine residue in their active site to catalyze the hydrolysis of peptide bonds in proteins. The mechanism involves the formation of an acyl-enzyme intermediate, which is then hydrolyzed to release the cleaved peptide. Trypsin, chymotrypsin, and elastases are secreted by the pancreas and work in conjunction with other digestive enzymes to break down proteins into smaller peptides and amino acids.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because carboxypeptidases are also serine proteases, but they are specific to the removal of amino acids from the C-terminus of proteins.
**Option B:** This option is incorrect because lipases are enzymes that break down triglycerides into fatty acids and glycerol, and are not involved in protein digestion.
**Option C:** This option is incorrect because collagenases are enzymes that break down collagen fibers, but they are not serine proteases and are not among the enzymes listed.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that trypsin, chymotrypsin, and elastases are activated by the duodenum's alkaline pH and work optimally in this environment. Inhibitors of these enzymes, such as aprotinin, can be used to prevent excessive bleeding during surgical procedures.
**Correct Answer: C. Serine proteases.