In the experiments conducted by Oswald Avery, Colin MacLeod, and Maclyn McCarty to determine the biochemical nature of the 'transforming principle', the addition of which of the following enzymes inhibited the transformation of R strain bacteria to S strain?

Step-by-step solution

Avery, MacLeod, and McCarty purified biochemicals (proteins, DNA, RNA, etc.) from the heat-killed S cells to see which ones could transform live R cells into S cells. They discovered that protein-digesting enzymes (proteases) and RNA-digesting enzymes (RNases) did not affect transformation, so the transforming substance was not a protein or RNA. Digestion with DNase did inhibit transformation, suggesting that the DNA caused the transformation. This proved that DNA is the hereditary material. Answer: DNase