When the patents on the SuperScript® II Reverse Transcriptase enzyme expired, a number of companies introduced their own version of the popular RT kit for cDNA synthesis. The advantage of these enzymes over traditional Moloney Murine Leukemia Virus Reverse Transcriptase (M-MuLV) is that they have been engineered to have greatly reduced RNAse H activity. RNAse H itself can be a useful enzyme for molecular biology as it specifically degrades RNA in a RNA:DNA hybrid, but it is clear to see how RNAse activity in an RT reaction is not ideal. In general the companies releasing alternatives to SuperScript® II RT aligned their pricing to be a bit less expensive then the popular Life Technologies kit. The strong brand loyalty molecular biology customers have, as we described in a previous post, meant that customers would continue to pay a higher price for SuperScript® II Reverse Transcriptase.