A protein inhibitor of acid deoxyribonucleases.

Proceedings of the National Academy of Sciences of the United States of America

PubMedID: 4905993

Lesca P, Paoletti C. A protein inhibitor of acid deoxyribonucleases. Proc Natl Acad Sci USA. 1969;64(3):913-9.
A protein extracted and partially purified (about 100-fold) from mouse liver is able to inhibit the acid DNases from different tissues and species, whereas pancreatic DNase and E. coli endonuclease I are not inhibited. The acid DNase displays typical Michaelis-Menten kinetics in the absence of this inhibitor, but the kinetics become sigmoidal in its presence. The existence of a DNase-inhibitor complex is demonstrated by physicochemical experiments. Moreover, the inhibitor is able to reactivate the DNase treated by urea, probably through a reassociation of the inactive monomers to a dimeric state. An allosteric model in which the DNase-inhibitor complex is composed of catalytic (DNase) and regulatory (inhibitor) subunits could explain these data.