Oswald Avery used different types of enzymes in his experiments to denature molecules including proteins and DNA. This way, he could determine which one was the "transforming principle". What was he able to conclude?

A. DNase, which was used to degrade DNA, prevented transformation.

B. Neither protease or DNase was able to prevent transformation.

C. Enzymes that degraded the proteins, proteases, prevented transformation.

The correct answer is A.

Oswald Avery applied several biochemical techniques to large cultures of bacteria in order to extract and purify the "transforming principle". Their experiments showed that most probably the "transforming principle" was DNA. One of the observations leading to this conclusion was that enzymes that degrade proteins or RNA (such ribonucleases) had no effect on the "transforming principle". On the contrary, enzymes degrading the DNA destroyed the extract's transforming capacity.