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Plasmid miniprep problem - (Jul/26/2005 )

Hi I am using miniprep for isolation of plasmids but after transforming E.coli XL1 blue with plasmid the isolation begins to give bad results.I have tried plasmid purification kit,PCR purification kit but all the time it isolated with impurities.I am sending a picture of isolation.If someone help me,, will be very greatful.Thank you.


seems you have enormous quantity of RNA in your prep...
try an alkaline lysis purification... and see that kits does not always do the job they are intented for...


maybe your prep is degraded (the smear at the bottom of your gel) and plasmid linearized (the bright band at he top)
try another miniprep and carefully work in the presence of EDTA



By the looks of your sample it appears that you have a high salt concentration (as indicated by the narrowing of the lane). Out of curiosity, which miniprep kit are you using?



The 23kD band is genomic dna... the rest is partially degraded RNA.

Start over using fresh reagents.