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enzymes
enzymes fpl

Enzymes and proteins act as catalysts inside cells. Mediators are substances that make chemical reactions continue, and there may be hundreds of reactions inside cells, each of which requires a specific enzyme.

Enzymes mediate either “synthesis” processes, forming complex compounds from simple molecules, or degradation processes, which disintegrate complex molecules into simple subunits by hydrolysis. Look . digestion

starch
As phosphoryl diastase realizes
Glucose


enzyme characteristics
Characteristics of enzymes

Enzyme features. (a) Enzymes are proteins.

(b) Enzymes work more effectively within narrow ranges of temperature. Human enzymes work best at a temperature of 37°C (body temperature). This is called the optimum temperature. The effectiveness of enzymes decreases above and below this temperature, and when the temperature exceeds 45°C. Most enzymes are destroyed (denaturation occurs).

The best temperature
Rate of action of enzymes

(c) Enzymes have an optimal pH at which they work most effectively. For example, the salivary enzyme (saliva amylase) works at a neutral or slightly acidic pH. The stomach enzyme pepsin only works at an acidic pH, while the intestinal enzyme trypsin prefers an alkaline pH.

pH
Enzyme action rate

(d) The rate of the reaction mediated by the enzyme increases with the concentration of the enzyme.

Reaction time
Enzyme action rate
Increased enzyme concentration

(e) The rate of the reaction mediated by the enzyme increases with the increase in the concentration of the affected substrate, the substance in which the enzyme acts, to a maximum point.

Concentration of the affected substance
Enzyme action rate

(f) An enzyme usually mediates only one specific reaction, a property called “specificity.”

For example: The catalase enzyme cannot metabolize anything other than hydrogen peroxide. Hydrogen peroxide + catalase water + oxygen -

2H2O2 starch + catalase
02 2H2O No reaction

Naming Enzymes Most enzymes are named by linking the suffix -ase to the enzyme of the substrate. For example: maltase activates maltose in maltose, urease activates urea, etc.


enzyme mechanism
mechanical enzymes

Enzyme mechanism. The work of the enzyme is explained by the “lock and key hypothesis.” The enzyme is likened to a lock that only certain keys (molecules of the affected substrate) can enter. In this way, the enzyme and the affected substance come together and the reaction takes place.

Enzyme molecule before the reaction
Particles of a substance affected during a reaction
After the interaction

The above sequence shows an enzyme-mediated synthesis. When the order is reversed, the diagrams show how the enzyme-mediated degradation occurs.