This theory was replaced by the induced fit model which takes into account the flexibility of enzymes and the influence the substrate has on the shape of the enzyme in order to form a good fit. As a result, the substrate will be stabilized. According to this theory, the enzyme and substrate shape do not influence each other because they are already in a predetermined perfectly complementary shape. Model 1: Lock and Key In this model, the shape of the active site and substrate complement in such a way that the substrate fits into the binding site. and enzyme, called the keylock hypothesis, was proposed by German chemist Emil Fischer in 1899 and explains one of the most important features of. Their complementary shapes make them fit perfectly into each other like a lock and a key. The theory behind the Lock and Key model involves the complementarity between the shapes of the enzyme and the substrate. At the active sites, the enzyme has a specific geometric shape and orientation that a complementary substrate fits into perfectly. Because the enzyme and the substrate are at a close distance with weak attraction, the substrate must need a matching shape and fit to join together.
It is assumed that both the enzyme and substrate have fixed conformations that lead to an easy fit. In the Lock and Key Model, first presented by Emil Fisher, the lock represents an enzyme and the key represents a substrate. In the Lock and Key Model, first presented by Emil Fisher, the lock represents an enzyme and the key represents a substrate. Emil Fischer (1894) proposed lock and key theory for the mechanism of enzyme act ion according to which the active sites of enzyme have a specific geometric. The model is based on a lock-and-key principle, where proteins interact only if one protein contains the lock aspect of some interaction surface, and the.