Explain with the help of a suitable example the naming of a restriction endonuclease.

Smith and Nathans proposed that the enzyme names should begin with a three‐letter acronym in which the first letter was the first letter of the genus from which the enzyme was isolated and the next two letters were the first two letters of the species name. Extra letters or numbers could be added to indicate individual strains or serotypes. 
For example, name of restriction endonuclease, EcoRI comes from Escherichia coli RYB strain. In EcoRI, 'E' comes from the genus 'Escherichia' and 'co' comes from the species name 'coli'. The letter 'R' is derived from the name of the strain RYB. Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria.