FIG. 4.

Low dNTP extension assay. The ability of the various enzymes to extend the −47 primer on an M13mp18 template was measured at a final concentration of either 0.1 or 0.5 μM each of the four dNTPs. The reactions were run as a time course with samples taken at 15, 30, and 60 min (see Materials and Methods). The reaction products were fractionated on a 6% polyacrylamide gel, and the DNA products were visualized by autoradiography. The scale at the left shows the sizes of the products. WT, wild type.