What is best for standard plasmid digests or for separating large DNA fragments?
Large DNA can also be run fast in a gel. If you use LB or SB, a commercially available high-strength agarose in a 0.3 to 0.5% gel is best to separate fragments over 2000 bp. If you prefer to use a standard agarose gel at 0.7 or 0.8%, use LA to optimally resolve large DNA fragments. LA is borate-free and tris-free and is a replacement for TAE for standard plasmid restriction digests. Borate, which is present in LB and SB, causes reversible crosslinks with DNA, reducing the separation of larger DNA fragments unless low % gels are made of high-strength agarose. See our tutorial on large DNA.
