Characterization of deoxyribonuclease activities derived from control and inflammation-associated mouse peritoneal macrophages.

Native DNAase (deoxyribonuclease) activities derived from mouse peritoneal cavity and peripheral blood components were separated, detected, and characterized by electrophoresis into polyacrylamide gels containing DNA, followed by incubation of the gels, and staining of the substrate to reveal only the DNAase activities. Resident peritoneal macrophages contained 12 DNAase-II-like activities that were characteristic of that cell type, whereas lymphocytes and granulocytes each contained five DNAases. Induction of inflammation by peritoneal injection of thioglycollate resulted in changes in macrophage DNAase expression, including: increased total DNAase activity, a decrease in the number of activities from 12 to 11, increased activity of a specific subset of the enzymes, and a change in the apparent size of a specific subset of the enzymes.

Isoelectric focusing--polynucleotide/polyacrylamide-gel electrophoresis. A technique to separate and characterize nuclease activities.

Individual native nuclease activities from human leucocytes are separated by using two-dimensional gel electrophoresis in an apparatus that allows the simultaneous running of 28 gels. Proteins are separated by isoelectric focusing in a disc gel, followed by electrophoresis into a slab gel containing DNA. Protein denaturants are avoided in the second dimension by the use of a running pH well above the optimal pH for DNAase (deoxyribonuclease) activity.

The effect of polyamines on the poly(adenylic acid)-induced inhibition of ribonuclease activity.

Segments of poly(A) at the 3'-termini of 5 S rRNA inhibit the activities of ribonucleases from Citrobacter, Enterobacter, bovine pancreas, human spleen and human plasma. Certain polyamines, or compounds containing polyamine substructures, mediate reversal of this inhibition. Effective compounds contain three amino groups, at least two of which are charged and are separated from the others by no less than three carbon atoms.

Poly(adenylic acid) in small amounts, free or covalently linked to substrate, protects RNA from hydrolysis by ribonuclease.

Short lengths (18 residues) of poly(A), covalently linked to the 3'-termini of Escherichia coli 5 S rRNA, induce powerful inhibitions (38-87%) of the activities of RNAases (ribonucleases) from Citrobacter sp., Enterobacter sp., bovine pancreas, human spleen and human plasma.

The ribonucleases of bovine skeletal muscle.

Bovine skeletal muscle contains small amounts of at least six heat- and acid-stable RNA-degrading enzymes. Our results are the first evidence for multiple ribonucleases in skeletal muscle. Three of these have been highly purified, and each has been shown to be a pyrimidine-specific endoribonuclease by use of a rapid sequencing technique employing gel electrophoresis.