Choose the correct statements about the naming of restriction enzymes:
A. The first letter of the name comes from the genus of the prokaryotic cell from which the enzyme was isolated.
B. The second two letters of the name come from the strain of the prokaryotic cell from which the enzyme was isolated.
C. The Roman number following the name shows the order in which the enzymes were isolated from that strain of bacteria.
D. In EcoRI, the letter ‘R’ is derived from the name of the strain.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A, C and D only
A restriction enzyme is named after the bacterium it comes from. The first letter stands for the genus, the next two letters for the species, then comes the strain, and a Roman number gives the order of isolation from that strain. EcoRI comes from Escherichia coli RY 13.
A. The first letter of the name comes from the genus of the prokaryotic cell from which the enzyme was isolated. — True. In EcoRI, E stands for the genus Escherichia.
B. The second two letters of the name come from the strain of the prokaryotic cell from which the enzyme was isolated. — False. The second two letters come from the species; in EcoRI, ‘co’ stands for coli.
C. The Roman number following the name shows the order in which the enzymes were isolated from that strain of bacteria. — True. The I in EcoRI shows that it was the first enzyme isolated from that strain.
D. In EcoRI, the letter ‘R’ is derived from the name of the strain. — True. R comes from the strain RY 13.
So statements A, C and D are correct.
NCERT Extract:
Restriction Enzymes – “… The convention for naming these enzymes is the first letter of the name comes from the genus and the second two letters come from the species of the prokaryotic cell from which they were isolated, e.g., EcoRI comes from Escherichia coli RY 13. In EcoRI, the letter ‘R’ is derived from the name of strain. Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria.”