The enzyme trypsin is specific for peptide bonds of:
**Core Concept**
The enzyme **trypsin** is a serine protease that plays a crucial role in protein digestion in the small intestine. It specifically cleaves peptide bonds, which are the chemical bonds that link amino acids together in a protein. The specificity of trypsin is determined by the type of amino acids involved in the peptide bond.
**Why the Correct Answer is Right**
Trypsin is specific for peptide bonds where the carboxyl group has been contributed by the amino acids **lysine** or **arginine**, except when either is followed by **proline**. This specificity is due to the shape and chemical properties of the trypsin active site, which is designed to recognize and bind to the positively charged side chains of lysine and arginine. The cleavage occurs on the carboxyl side of these amino acids.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because trypsin does not specifically target peptide bonds involving other amino acids as its primary site of action.
**Option B:** Similarly, this option is incorrect as it does not accurately describe the specificity of trypsin.
**Option D:** This option is also incorrect as it misrepresents the target of trypsin's enzymatic activity.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that trypsin's specificity for lysine and arginine is a critical aspect of its role in protein digestion and can be relevant in various clinical contexts, including pancreatic enzyme replacement therapy.
**Correct Answer:** D. lysine or arginine