What characteristic defines restriction enzymes?

Restriction enzymes, also known as restriction endonucleases, are specialized proteins that recognize and cut DNA at specific sequences of nucleotides. These specific sequences are usually palindromic, meaning that the same sequence of bases reads the same in the forward and reverse directions. This property allows restriction enzymes to cut DNA into manageable fragments, which is a crucial aspect of molecular biology techniques such as cloning, DNA mapping, and genetic engineering.

The precision with which restriction enzymes operate is key to their utility in molecular biology. By targeting defined sequences, they enable scientists to isolate specific genes or DNA segments for further analysis or manipulation. This characteristic distinguishes restriction enzymes from other nucleases that may cut DNA or RNA more randomly or non-specifically. By utilizing these enzymes, researchers can construct recombinant DNA molecules or perform precise genotyping, among other applications.