Naming of enzymes Over 150 different restriction endonucleases have been identified Isolated from different bacteria Recognize specific DNA sequences which are usually 4-8 bp long Escherichia coli yields several different enzymes, one is called EcoRI. The E is derived from the genus, and the second and third letters (co)# from the species name. The numbers refer to the strain in this case RY13.Naming of enzymes • Over 150 different restriction endonucleases have been identified. • Isolated from different bacteria • Recognize specific DNA sequences which are usually 4-8 bp long • Escherichia coli yields several different enzymes, one is called EcoRI. The E is derived from the genus, and the second and third letters (co) # from the species name. The numbers refer to the strain, in this case RY13