RNase H type-2 (PS51975) The ribonuclease H (RNase H) (EC 3.1.26.4), which is part of the ribonuclease family, can find and cut the RNA strand in RNA-DNA heteroduplexes. Type I and II RNase H share similar structural characteristics of the catalytic domain; however, they utilize distinct substrate ranges for enzymatic cleavage. Archaea, eubacteria, and all eukaryotes contain RNase HII.