AGB-0030
QUESTION
Treatment with proteolytic enzymes cuts a 323-residue piece containing the 5’- 3’ exonuclease from DNA polymerase I leaving a larger C-terminal piece know as?
OPTIONS
(A) Replisome
(B) Okazaki fragments
(C) Klenow fragment
(D) DNA polymerase II
ANSWER
(C) Klenow fragment
EXPLANATION
Proteolytic treatment of DNA polymerase I removes the amino-terminal portion containing the 5′→3′ exonuclease activity and leaves the larger C-terminal Klenow fragment, which retains DNA polymerase and 3′→5′ exonuclease activities. A replisome is a DNA-replication complex, Okazaki fragments are short lagging-strand DNA fragments, and DNA polymerase II is a different polymerase.