Figure 1. Purified Northern shrimp nuclease and its DNA substrates.

The enzyme after SDS-PAGE and silver-staining (A), its hydrolyzing activity on different DNA substrates (B), and ligation of its digestion products (C) as analyzed by agarose gel electrophoresis. Activities of two preparations of the shrimp dsDNase (1a and 1b) and of a shrimp ss nuclease (2) on a dsDNA PCR product, a heat denatured PCR product (ds+ssDNA) and on supercoiled plasmid DNA are shown. M defines the lane of protein MW standards and of a 100 bp DNA ladder in the relevant gel types, and lanes C represent the respective untreated DNA substrates used. Lane R shows the ligated reaction products from dsDNase digested plasmid DNA.