FAQ: What is the difference between E. coli RNase H (NEB #M0297) and Thermostable RNase H (NEB #M0523)?

Both Thermostable RNase H and E. coli RNase H cleave RNA in a DNA:RNA hybrid molecule while leaving the DNA intact; they do not cleave single- or double-stranded RNA or DNA.  However, Thermostable RNase H is active over a wider temperature range than the E. coli enzyme, with optimal activity at 65°C, and a range of activity from 37°C - 95°C.