The lock-and-key mechanism refers to

The Correct Answer is:

Emil Fischer was the first to describe the Lock-and-Key mechanism, which involves an enzyme momentarily binding to one substrate to generate a substrate complex.

Complementary enzyme forms that share a single substrate are frequently related to the locking mechanism and key, with the enzyme functioning as the lock and the substrate as the key. One substrate (key) fits neatly into the enzyme’s active site (keyhole) (lock).

Physically, the substrate and the active site indicated above are compatible. This is the enzyme’s temporary binding site. Like a lock and a key, the enzyme is designed to fit the lock and the substrate together.