DNase,RNase, and phosphatase activities of antibodies formed upon immunization by DNA,DNase I,and DNase II

Relative DNase, RNase (efficiency of hydrolysis of ribo- and deoxyribooligonucleotides (ON)), and phosphatase (removal of the ON 5′ terminal phosphate) catalytic activities of antibodies (AB) obtained after rabbit immunization by DNA, DNase I, and DNase II were compared. It is shown that electrophoretically homogeneous preparations of polyclonal AB from non-immunized rabbits did not exhibit such activities. Immunization of rabbits by DNA, DNase I, and DNase II results in generation of IgG abzymes that exhibit high activity in the ON hydrolysis reaction and even higher activity in cleavage of 5′ terminal phosphate of ON. In this case K _m values for supercoiled plasmid DNA and ON found in reactions of their AB-dependent nuclease hydrolysis and phosphatase cleavage of 5′ terminal phosphate differ by 2–4 orders of magnitude. This shows that nuclease and phosphatase activities belong to different abzyme fractions within polyclonal AB. Thus, in this work data indicative of the possibility of a formation of antibodies exhibiting phosphatase activity after immunization of animals with DNA, DNase I, and DNase II, were obtained for the first time. Possible reasons for production of AB with phosphatase activity after immunization of rabbits with these immunogens are discussed.