Some properties of alkaline DNases of tentacles of actinia Radianthus macrodactylus and their hemolytic activity

Two alkaline DNases of tentacles of actinia Radianthus macrodactylus, refer red to as alk DNase I and alk DNase II, respectively, have been purified up to apparent homogeneity with consecutive column ion exchange chromatograph y and gel filtration. Both enzymes have a lot of common properties, such as the ability to hydrolyze Very effectively p-nitrophenyl-5'-TMP and heat-de natured DNA. They both have no preferential specificity to the sugar compon ent of the nucleic acids and effectively digest ribopolymers. Their ability to hydrolyze supercoiled DNA of the pBR322 plasmid and linear DNA of the l ambda phage by "miscellaneous" exo- and endonucleolytic types of attack and to produce nucleosides, nucleotides and short oligonucleotides suggests th eir similarity with phosphodiesterase I (5'-exonuclease, oligonucleate 5'-n ucleotidohydrolase; E.C. 3.1.4.1), isolated from rattle snake Crotalus adam enteus venom. Alk DNase II has been revealed to have some uncommon properti es, such as phosphomonoesterase and hemolytic activities. The protein cause s a very potent lysis of human and rabbit erythrocytes. The ability of alk DNase II to precipitate some components of normal human and rabbit blood se rum as well as the inhibition of this reaction by fucose but not by another monosaccharides suggest the enzyme to have a lectin-like activity. The app earance of only one protein band during electrophoresis of alk DNase II in denaturation conditions suggests that all activities are inherent to the sa me molecule of protein. The possible role of alkaline DNases in the toxic e ffect of burning by actinia tentacles is discussed. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.