Best method for blunting ds DNA?

Tom Chappell dmcbtch at
Mon Oct 10 16:04:56 EST 1994

In article <377lgd$br9 at nntp.Stanford.EDU>
webam at adelbert12.Stanford.EDU (Annie Yang) writes:

> I wonder how people can clip 3' overhang w/ Klenow, since
> the Read book clearly states that Klnow is not suitable for
> this purpose.
> Hong Yang @
> hyang at

Klenow definitely has  3'-> 5' exo activity that will chew back 3'
overhangs. (It lacks the 5'->3' exo of the full pol I). T4 is just so
much more efficient at the 3'->5' exo reaction that it is a much better
enzyme to use for removing 3' overhangs.

Tom Chappell
MRC Lab for Mol. Cell Biology  

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