Nitrogen and carbon are more abundant in proteins than sulfur. Why did Hershey and Chase use radioactive sulfur instead of nitrogen and carbon to label the protein portion of their bacteriophages in their experiments to determine whether parental protein or parental DNA is necessary for progeny phage production?

Hershey and Chase experiment confirms that DNA is the genetic material of the living organism, not the RNA or protein. They also got a noble prize for this discovery.

Hershey and Chase use the radioactive sulfur to label the proteins and distinguish them from the DNA because DNA do not contain sulfur. The radioactive label phosphorus was used to label the DNA as phosphorus is specific to DNA as they wants to know exactly the genetic material. They do not use the radioactive carbon and nitrogen because both carbon and nitrogen are present in DNA and RNA. This labeling may produce confused result as it label both DNA as well as protein. The result o radioactive phosphorus and sulfur determines that DNA is the genetic material of the organism.