The “Lock and key” theory of enzyme action was put forward by

The correct option is Fischer.

The "Lock and Key" theory of enzyme action is a fundamental concept in biochemistry that explains how enzymes interact with their specific substrates. This theory was proposed by the German chemist Emil Fischer in 1894.

According to Fischer's model:
1. The active site of an enzyme has a rigid, specific geometric shape.
2. The substrate has a complementary shape that fits precisely into the active site, much like a specific key fits into a unique lock.
3. This highly specific binding explains why enzymes are extremely selective and only catalyze reactions for specific substrates.

Here is a brief overview of the other scientists mentioned in the options to clarify their contributions:
• Koshland proposed the "Induced Fit" theory in 1958, which suggested that the active site is flexible and molds around the substrate upon binding.
• Kuhne coined the term "enzyme" in 1878.
• Arrhenius is known for his work on chemical kinetics and the Arrhenius equation relating to activation energy, rather than the mechanism of enzyme-substrate binding.