LabBench Activity

How Do Restriction Enzymes Work?

Like all enzymes, restriction enzymes are highly specific. They cut DNA only within very precise recognition sequences. Study the illustrations below to see three different recognition sequences. The red line shows where the enzymes will cut the DNA. Notice that all of these recognition sites are symmetrical, or what is called "palindromic." This means that the recognition sequence on one DNA strand reads in the opposite direction on the complementary strand.

Next let's look at the laboratory procedures for cutting and separating DNA fragments.