Bst DNA Polymerase Activity Assays
Bst DNA polymerase activity was determined by a cDNA synthesis reaction using a synthetic single-stranded template and primer complementary to a portion of the template. Detection of the cDNA strand was accomplished by hybridizing the polymerase product with an acridinium ester-labeled probe designed to be complementary to the cDNA strand. The labeled double-stranded hybrid was detected using the hybridization protection assay (HPA) as described in Arnold et al., Clin. Chem. 35:1588-1594 (1989) and Arnold et al., U.S. Pat. No. 5,283,174, the latter of which enjoys common ownership with the present application and both of which are hereby incorporated by reference herein. The sample suspected of containing Bst DNA polymerase was incubated in a reaction mixture containing 50 mM Tris (pH 7.5), 25 mM KCl, 4 mM MgCl2, 2 mM spermidine, 0.2 mM each dNTP at 60° C. for 8 minutes with 20 fmol of an 86 base pair synthetic DNA template derived from bacteriophage T7 gene 10 plus 30 pmol of a 23 base primer complementary to the 3' end of the template strand. The reaction mixture was incubated at 95° C. for 3 minutes to denature the DNA strands, then incubated at 60° C. for 10 minutes with 1.5 pmol of the acridinium ester labeled detection probe. Unhybridized probe was hydrolysed at 60° C. for 7 minutes with an alkaline borate buffer and the remaining chemiluminescence, contributed by the hybridized labeled probe, was measured in a LEADER 1™ luminometer, (Gen-Probe Incorporated, San Diego, Calif.), after injection of a dilute solution of H2 O2 and a solution of sodium hydroxide.
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