How is specificity determined by the serine proteases?

Proteases preferentially hydrolyze the peptide bonds of polypeptide substrates depending on the amino acids preceding and/or following the cleavage site. The substrate residue N-‐terminal to the cleavage site (P1) largely determines the specificity of serine proteases.

Why is it necessary that serine proteases are regulated?

Trypsin, a powerful digestive enzyme, is generated in the pancreas. Inhibitors prevent self-digestion of the pancreas itself. Serine proteases are paired with serine protease inhibitors, which turn off their activity when they are no longer needed.

What substrate does protease catalyze?

A protease (also called a peptidase or proteinase) is an enzyme that catalyzes (increases reaction rate or “speeds up”) proteolysis, the breakdown of proteins into smaller polypeptides or single amino acids. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds.

What enzyme is serine protease?

Chymotrypsin as a Model Enzyme The first serine protease scientists explored in detail was chymotrypsin, a digestive enzyme synthesized in our pancreas, along with the related enzymes trypsin and elastase. It is transported to our small intestine in an inactive form.

Which one of the following is an example of serine protease?

Chymotrypsin: >Used as an example of a serine protease because it’s structure and mechanism are well understood.

How is specificity determined by chymotrypsin?

A specific pocket adjacent to the active site triad determines the specificity of the protease (chymotrypsin cleaves adjacent to large aromatic side chains, trypsin adjacent to lys or arg residues). These are amino acids 189, 216 and 226 which line a pocket adjacent to the active site triad.

Why does trypsin recognize and cleave a different sequence when compared to elastase?

Trypsin cleaves at the peptide bond after residues with long, positively charged side chains—namely, arginine and lysine—whereas elastase cleaves at the peptide bond after amino acids with small side chains—such as alanine and serine. Comparison of the S1 pockets of these enzymes reveals the basis of the specificity.

Which of the following is an example of cysteine proteases?

Cysteine proteases are commonly encountered in fruits including the papaya, pineapple, fig and kiwifruit. The proportion of protease tends to be higher when the fruit is unripe. In fact, dozens of latices of different plant families are known to contain cysteine proteases.

What are serine proteases give an example?

Clan PA proteases bearing the trypsin fold are the largest family of serine proteases and perhaps the best studied group of enzymes. Digestive enzymes such as trypsin and chymotrypsin cleave polypeptide chains at positively charged (Arg/Lys) or large hydrophobic (Phe/Trp/Tyr) residues, respectively.

Why are they called serine protease?

Serine proteinases are the largest class of mammalian proteinases. They are so called because they have a catalytically essential serine residue at their active sites. Serine proteinases are optimally active at neutral pH and play major roles in extracellular proteolysis.

What is a specificity pocket?

The specificity pocket provides a small binding pocket consisting of 3 amino acid residues that determine the local polarity and electrostatic potential profile for the interaction of residue n-1 on the substrate on the N-terminal side of the scissile bond.

How is specificity determined by the serine proteases? Proteases preferentially hydrolyze the peptide bonds of polypeptide substrates depending on the amino acids preceding and/or following the cleavage site. The substrate residue N-‐terminal to the cleavage site (P1) largely determines the specificity of serine proteases. Why is it necessary that serine proteases are regulated? Trypsin, a…