In 1866 the Austrian Monk, Gregor Mendel, discovered the laws of heredity. In the early 1900s the units of heredity were located in the central nucleus of cells and were called genes. Watson and Crick revealed the secret of genes, of heredity, of reproduction and replication. As in our world you can actually have different words naming the same thing. These sentences are what we call genes.
Structural proteins serve to build all sorts of components inside the cell and around it.
Catalytic proteins, or enzymes, carry out the thousands of chemical reactions that take place in any given cell, e.g., breakdown of foodstuff, retrieval and consumption of energy. Life, in other words. We knew the alphabet used to write its 50,000 to 100,000 volumes. We had even discovered a few titles, like the amino acid sequence of insulin. But we had no systematic way of finding which books lay in which wing and in which shelf.