In Experimental Tests of Enzyme Evolution, a Gene Encoding an Enzyme

Multiple Choice

In experimental tests of enzyme evolution, a gene encoding an enzyme was subjected to multiple cycles of random mutagenesis and selection for altered substrate specificity. The resulting enzyme had altered substrate specificity and multiple amino acid changes. Where in the enzyme would you expect these amino acid changes to be located?

A) only in or near the active site
B) only in the hydrophobic interior of the folded protein
C) only at surface sites distant from the active site
D) in or near the active site and at surface sites distant from the active site