What does the lock and key feature of enzymes indicate?

What does the lock and key feature of enzymes indicate?

The specific action of an enzyme with a single substrate can be explained using a Lock and Key analogy first postulated in 1894 by Emil Fischer. In this analogy, the lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).

What is the process of lock and key model of enzymatic action?

Enzymes are folded into complex shapes that allow smaller molecules to fit into them. In the lock and key model, the shape of the active site matches the shape of its substrate molecules. This makes enzymes highly specific – each type of enzyme can catalyse only one type of reaction (or just a few types of reactions).

How do you measure enzyme activity?

Enzyme activity = moles of substrate converted per unit time = rate × reaction volume. Enzyme activity is a measure of the quantity of active enzyme present and is thus dependent on conditions, which should be specified.

What are the 4 steps for enzyme action?

Four Steps of Enzyme Action

  • The enzyme and the substrate are in the same area. Some situations have more than one substrate molecule that the enzyme will change.
  • The enzyme grabs on to the substrate at a special area called the active site.
  • A process called catalysis happens.
  • The enzyme releases the product.

How do you know if an enzyme is active?

If the substrate is present, the enzyme will do its job. Other enzymes have to be made active. These enzymes aren’t lazy, they are just tightly regulated by molecules called effectors or in other ways that will be described. If an effector is required to regulate an enzyme, the enzyme is an allosteric enzyme.

How are active enzymes identified?

The easiest way to distinguish between them is to check whether the reaction rate is determined by the concentrations of the general acid and base. If the answer is yes then the reaction is the general type. Since most enzymes have an optimum pH of 6 to 7, the amino acids in the side chain usually have a pKa of 4~10.

What is lock and key hypothesis?

The lock and key hypothesis states that the substrate fits perfectly into the enzyme, like a lock and a key would. Since, the substrate binds to a specific enzyme, this hypothesis is meant for the substrate specific enzymes.

What are the 4 factors that affect enzyme activity?

Several factors affect the rate at which enzymatic reactions proceed – temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators.

What is the difference between active and inactive enzymes?

Enzymes are proteins that can change shape and therefore become active or inactive. This transformation enables the enzyme to better bind with its substrate (light pink puzzle piece). In contrast, an inhibitor molecule (pink circle) can prevent the interaction of an enzyme with its substrate and render it inactive.

How are enzymes inactivated?

Enzyme inactivation can principally be attributed to mechanisms related to the reactor, the medium components, or the protein. In the case of air bubbles and droplets of nonpolar organic solvents, interfacial interaction with the enzyme results in hydrophobic forces that disturb the secondary structure of the enzyme.

What is the optimum temperature for enzyme activity?

This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells. Above this temperature the enzyme structure begins to break down (denature) since at higher temperatures intra- and intermolecular bonds are broken as the enzyme molecules gain even more kinetic energy.

What are the 4 properties of an active site?


  • Bond Specificity: It is also called as relative specificity.
  • Group Specificity: It is also called structural specificity.
  • Substrate Specificity: It is also called absolute specificity.
  • Optical Specificity: It is also called stereo-specificity.

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