The Deoxyribonucleases of Streptococcus Pyogens.

Streptococci of serological groups A and C are known to produce substantial amounts of extracellular deoxyribonuclease (l-4). Evidence that the nuclease activity is probably due to the presence of more than one enzyme was suggested by the finding of Bernheimer (5) that ribonucleic acid from a variety of sources could inhibit to varying degrees the DNase activity of group A streptococci but did not effect the DNase activity of group C organisms. Subsequently, Wannamaker (6), using starch block electrophoresis, showed that culture supernatant solutions derived from streptococci contained three immunologically distinct DNase activities. A fourth DNase has since been isolated in this laboratory (7) and by Wannamaker (8). Two of these enzymes, DNases B and D, have been reported by the latter author to be inhibited by ribonucleic acid and to show ribonuclease act,ivity. However, the specificity of action of only one of these enzymes, streptodornase, or DNase A has been studied in detail (9, 10). In this report, we have investigated the conditions for optimal activity and the action of all four enzymes on deoxyribonucleic acid.