What is the specificity pocket of chymotrypsin?

P1 binds S1, which is called the specificity pocket; its interactions were found early on to be a major determinant of the substrate specificity for trypsin, chymotrypsin and elastase. S1 is near the catalytic triad (the region boxed below) and is made of protease residues that interact with the P1 residue.

What type of specificity is chymotrypsin?

The highly homologous S1 specificity sites of chymotrypsin and other pancreatic serine proteinases such as trypsin and elastase are built up from peptide segments 189–195, 213–220 and 226–228. The P1 residue of the substrate is known primarily to contact the main chain atoms of these regions.

What determines the specificity of chymotrypsin?

The Active Site Environment 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).

What amino acid residues does chymotrypsin recognize?

The main substrates of chymotrypsin are peptide bonds in which the amino acid N-terminal to the bond is a tryptophan, tyrosine, phenylalanine, or leucine.

What is in the hydrophobic pocket of chymotrypsin?

In chymotrypsin, this pocket is lined with hydrophobic amino acids, so substrate proteins with hydrophobic amino acids, such as leucine or isoleucine, bind tightly and in the correct orientation for the catalytic triad to function.

How many residues are in chymotrypsin?

α-Chymotrypsin is a serine protease of the peptidase S1 family consisting of 241 amino acid residues. The molecule has three peptide chains: an A chain of 13 residues, a B chain of 131 residues, and a C chain of 97 residues.

What residues does chymotrypsin cut?

Chymotrypsin (EC 3.4. 21.1) is a 26kDa serine carboxypeptidase that preferentially cleaves the amide bond (the P1 position) of an aromatic amino acid residues such as tyrosine, tryptophan and phenylalanine.

What are the important catalytic residues of enzyme chymotrypsin?

1 A). In the chymotrypsin index, His-57, Asp-102, and Ser-195 form the catalytic triad, residues 189–195, 214–220, and 225–228 form the primary substrate-binding pocket called S1 binding pocket.

How is chymotrypsin specificity determined?

How is specificity determined? Chymotrypsin is a member of a family of enzymes all of which cleave peptide bonds through the action of an active site serine (the serine proteases).

What are the active site residues of chymotrypsin?

The active site residues (ser-195, his-57 and ser-102 shown here as spacefilling) are far apart in the primary sequence but are brought together in a crevice formed between the two protein domains. The active site of chymotrypsin consists of asp102 positioned close to his 57 and ser 195.

What is chymotrypsin?

Tutorial developed by Ross Feldberg, Dept. of Biology, Tufts University How is specificity determined? Chymotrypsin is a member of a family of enzymes all of which cleave peptide bonds through the action of an active site serine (the serine proteases).

What is the stability of frozen chymotrypsin aliquots?

The presence of calcium is also a stabilizer. 5 Frozen aliquots are stable for approximately 1 week. Chymotrypsin is both activated and stabilized by Ca 2+.