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Page 1 (in Ch.7)
Page 3 Active
Page 4 Diagrams
Page 5 Reaction Mechanism Page 6 Crystal Structures Page 7 References
The two domains are different colours
Recall that chymotrypsin consists of three chains, due to several cleavages of the initial zymogen polypeptide. These chains are joined by disulphide bonds. Trypsin on the other hand is a single chain, as the zymogen is activated by removal of the first six residues. There is a marked difference between the conformation of four regions (called the activation domain ) of the trypsin polypeptide compared to its zymogen (Stroud et al, 1977; Huber and Bode, 1978).
Gail Schuman has produced this material on the trypsin zymogen, trypsinogen.
Although the serine proteases have no absolute specificity, they have strong preferences for the peptide bonds adjacent to specific amino acid residues. The important side chain is the one preceding the scissile bond (i.e. the one which is cleaved) in the sequence, that is, R in the above diagram.
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