Restriction enzymes are enzymes that break apart DNA into fragments or genes. They were originally created by bacteria as a defense mechanism to break down foreign DNA. There are three main types of restriction enzymes that recognize and cut DNA sequences in different ways. Restriction enzymes are commonly used to cut DNA into fragments for easier study and identification of genes, as well as recombining DNA molecules from different genomes to study gene expression and regulation.

2. What Are They?
• Restriction Enzymes are enzymes that have
been found in bacteria or invented in a lab.
• Restriction Enzymes are used to break apart
DNA into individual fragments or genes.

3. How Do They Work?
• Restriction Enzymes are actually enzymes
created by bacteria which the bacteria used to
defend it’s self against DNA by breaking down
any foreign DNA it came in contact with.
Scientists Werner Arber and Stuart Linn found
the specific section of DNA that did this and
named it EcoB. This is the first named
restriction enzyme.

4. How Much Do They Cost?
• Restriction Enzymes can be bought on the
internet.
• Their prices run from $20 for 1,000 units to
$500 for 1,000 units.
• Price based on demand for the enzyme in
research.

5. Types Of Restriction Enzymes
• Type 1: enzymes recognize DNA sequences
but cut the DNA in random sites that can be as
far as 1,000 base pairs away from the
recognized site.
• Type 2: enzymes recognize and cut within the
recognized site.
• Type 3: enzymes recognize sequences but cut
at a different location within 25 base pairs of
the recognized site.

6. Ways to Use Them
• First major way is to cut DNA into fragments
so that it would be easier to study, identify
and characterize genes.
• Second major way was to use a device for
recombining, or joining, DNA molecules from
different genomes. Usually used to identify
and characterize a gene or studying gene
expression and regulation.