DNase-I-like enzyme from the carp liver--inhibition by muscle and endogenous actin

1. DNase-I-like activity occurs in the carp (Cyprinus carpio) liver cytosol (supernatant 105,000 g). 2. The enzyme resembles DNase I from bovine pancreas in respect to the molecular mass (approximately 31 kDa), pH (7.4) and ion requirements (Mg2+, Ca2+) and the ability to degrade native as well as denatured DNA. 3. As judged by comparison of DNase zymograms obtained after native- and SDS-PAGE, the enzyme occurs in the three molecular forms of similar molecular weight and different charges. 4. All these forms are inhibited by rabbit skeletal muscle actin as well as by endogenous actin isolated from the carp liver cytosol. 5. DNase from the carp liver cytosol does not interact with the antibodies directed against DNase I from bovine pancreas and against DNase I from the rat and bovine parotid glands.