3 replies to this topic

[rimal]

I have 7 years stored plasmid with helicase activity, AND willing to use it in a major experiment, do I need to measure the the activity of helicase again after long term storage???

[bob1]

You have a plasmid that encodes helicase?  Or do you you have some helicase that has been stored for 7 years?  For the former, it should be fine, unless the plasmid has degraded as the plasmid will generate fresh helicase on transfection.  For the latter, you should check the activity before using.

[rimal]

bob1, on 13 September 2010 - 04:21 PM, said:

You have a plasmid that encodes helicase?  Or do you you have some helicase that has been stored for 7 years?  For the former, it should be fine, unless the plasmid has degraded as the plasmid will generate fresh helicase on transfection.  For the latter, you should check the activity before using.

it is a plasmid of a protein that possess helicase activity.

[HomeBrew]

You have no helicase enzyme stored to check the activity of -- you have a gene that encodes a helicase.  So, your concern should be with the integrity of the DNA of both the helicase gene and of the plasmid encoding it.

Is the plasmid stored as DNA or is it frozen in a host strain (of E. coli, perhaps)?

If it has been stored as DNA, transform a compatible bacterial strain, recover fresh plasmid DNA, and have the insert sequenced to insure integrity of the DNA.