Step 1: Identify the enzyme mentioned.
The enzyme polynucleotide phosphorylase is involved in the in-vitro synthesis of RNA. This enzyme played an important role in early molecular biology experiments related to the understanding of the genetic code.
Step 2: Recall the scientist associated with its discovery.
The enzyme polynucleotide phosphorylase was discovered by the American biochemist Severo Ochoa. His work on RNA synthesis contributed significantly to molecular genetics and helped scientists study how nucleotides form RNA chains.
Step 3: Significance of the discovery.
This discovery helped researchers produce artificial RNA molecules in the laboratory, which later played a major role in experiments that helped decipher the genetic code.
Final Answer:
The enzyme polynucleotide phosphorylase was discovered by Severo Ochoa.