your enzyme cannot give definite fragment. thus smear
发自网易邮箱大师 在2017年09月30日 19:28，Mohammad Khan 写道： Dear all, I am working with an exonuclease and I run the digested DNA on a 8Murea-20%acrylamide gel in TBE buffer. I use the Mini-Protean BioRad system and cast gels of about 8.6x6.5 cm dimensions with 1.5 mm thickness. I use a 15 well comb. I run my gels at 70 V for as long as 4 hours till my undigested DNA reaches half the gel distance. I use 20-30 nt long susbtrates. I am mostly not able to get distinct bands of the digested products but rather get a smear. Is there any way to make sure that I get distinct digested products rather than a smear? I am looking forward for suggestions from all! Thank you. Ciao!
