In considering the 'active site' of enzymes, a fair generalization is that
A) nearly all the amino acid side-chains of the protein must directly participate in catalysis.
B) all the amino acid residues which are involved in the active site are adjacent because they are located on the same short stretch of the polypeptide backbone.
C) the conformation of the active site region does not exist at all until the substrate is bound.
D) the amino acid residues which form the active site are in close proximity because of the specific three-dimensional conformation the protein has adopted.
E) only one amino acid residue is involved in the active site.

Question

Quizplus · Accepted Answer

The active site of an enzyme is a specific region where the substrate binds and the chemical reaction takes place. The amino acid residues that form the active site are positioned in close proximity to each other because of the specific three-dimensional conformation that the protein adopts. This close positioning is necessary for the amino acids to interact with the substrate and catalyze the chemical reaction. Therefore, the best choice is D.

In Considering the 'Active Site' of Enzymes, a Fair Generalization