magic? - got more product after PCR purification... (Dec/29/2005 )
I am so so so confused! I did PCR i went great i got only one band so I purified the product and checked the OD and I had 280 ng of DNA...so I was happy and went on digested the vector and my PCR product with HindIII and EcoRI and purified both by heat inactivation and chloroform extraction.....I take the OD again and now I have 1ug of PCR product...!!!!! 
...vector OD was very fine with some loss.....what could happen??? how could my PCR product suddenly get 5 times more??? ? was Taq and primers and dNTPs not destroyed and they did PCR again when I heated the sample at 65 to destroy the enzymes??? did anyone had the same problem??? thanx a lot.
Don't just trust your OD values, if you want to be more sure check your PCR on gel after purification and compare the concentration with your DNA ladder.
OD values are very error prone, there are some topics about it elsewhere on this forum, don't know exaclty where though.
OD values are very error prone, there are some topics about it elsewhere on this forum, don't know exaclty where though.
it just seems so strange that OD would read 5 times more or less....
....I am doing ligation right now so if everything goes fine ill forget about it....but if not will check by gel next time...
I would trust a gel over an OD reading any day.
You probably have at least 240 ng.
-Matt