The Ladderman DNA Labeling Kit is a novel random primer labeling system that takes advantage of longer primers and Bca polymerase, a thermostable DNA polymerase isolated from Bacillus caldotenax. Unlike the E. coli Klenow fragment or modified T7 DNA polymerase, thermostable Bca polymerase allows stable polymerization of DNA even when using high GC content templates containing highly structured regions. Longer 9-mer primers increase the incorporation efficiency of labeled nucleotides up to 80%.
With the Ladderman DNA Labeling Kit kit, random primer labeling via thermostable Bca polymerase is accomplished within 10 minutes, resulting in significant amounts of labeled DNA probe. The kit is designed for use with [32P]-alpha-, [35S]-alpha- or [3H]-alpha-dCTP labels, but it can also be used with nonradioactive biotin, digoxigenin or DNP-labeled dUTPs through dNTP replacement. In general, probes with specific activities of >109 dpm/mg DNA are obtained with [32P]-alpha-dCTP (~3,000 Ci/mmol, 111 TBq/mmol).