Figure 3-39. An unusually reactive amino acid at the active site of an enzyme.

Figure 3-39An unusually reactive amino acid at the active site of an enzyme

This example is the “catalytic triad” found in chymotrypsin, elastase, and other serine proteases (see Figure 3-14). The aspartic acid side chain (Asp 102) induces the histidine (His 57) to remove the proton from serine 195. This activates the serine to form a covalent bond with the enzyme substrate, hydrolyzing a peptide bond.

Image ch3f14

From: Protein Function

Cover of Molecular Biology of the Cell
Molecular Biology of the Cell. 4th edition.
Alberts B, Johnson A, Lewis J, et al.
New York: Garland Science; 2002.
Copyright © 2002, Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter; Copyright © 1983, 1989, 1994, Bruce Alberts, Dennis Bray, Julian Lewis, Martin Raff, Keith Roberts, and James D. Watson .

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