Back to: MICROBIOLOGY 200 LEVEL
Welcome to class!
Hello my ever-curious and brilliant learner! I’m super glad to have you here today. You know, just like how your performance in school depends on things like enough sleep, good food, and a peaceful environment, enzymes also need the right conditions to work well. Today, we’re going to look at something really important—Factors Affecting Enzyme Activity. By the end of this class, you’ll understand exactly why enzymes sometimes work fast, slow, or not at all.
Factors Affecting Enzyme Activity
What Is Enzyme Activity?
Enzyme activity refers to how well or how fast an enzyme carries out its job—breaking or building substances during a chemical reaction. For enzymes to perform at their best, they need the right environment, just like how NEPA needs stable electricity to power your appliances. If conditions aren’t right, enzyme activity can slow down or stop completely.
Let’s break down the major factors that affect enzyme activity:
1. Temperature
Enzymes are sensitive to heat. They have an optimum temperature at which they work best. For most human enzymes, it’s around 37°C (normal body temperature).
If the temperature is too low, enzyme activity slows down—like a cold engine.
If the temperature is too high, the enzyme can become denatured (its structure breaks down and it stops working).
2. pH (Acidity or Alkalinity)
Each enzyme has an optimum pH at which it works best.
If the pH is too acidic or too alkaline, the enzyme may lose its shape and function.
For example, pepsin, an enzyme in the stomach, works best in acidic conditions (pH 2), while amylase in saliva prefers a neutral pH (around 7).
3. Substrate Concentration
The substrate is the substance the enzyme acts upon.
If substrate concentration increases, enzyme activity also increases—but only up to a point.
Once all enzyme molecules are “busy,” the reaction rate levels off (this point is called enzyme saturation).
4. Enzyme Concentration
Increasing the number of enzyme molecules can increase the rate of reaction—if there’s enough substrate available.
But if there’s too little substrate, adding more enzymes won’t make much difference.
5. Presence of Inhibitors
Inhibitors are substances that slow down or stop enzyme activity.
They can be competitive (compete with the substrate) or non-competitive (attach elsewhere and change the enzyme’s shape).
Imagine someone blocking a tap or pressing the wrong keys on your keyboard—nothing will work properly.
Think of a mama frying akara:
If the fire is too low (low temperature), the akara takes forever.
If it’s too hot (high temperature), it burns quickly.
If there’s too much batter (substrate) but not enough oil (enzymes), she has to wait.
If someone adds salt when she needs sugar (wrong pH or inhibitor), it won’t taste right.
Enzymes work the same way—they need just the right environment.
Summary
- Enzymes work best under specific conditions.
- The main factors affecting enzyme activity are temperature, pH, substrate concentration, enzyme concentration, and presence of inhibitors.
- If any of these are out of balance, enzyme function can slow down, stop, or be permanently damaged.
Evaluation
- What is meant by “optimum temperature” for an enzyme?
- How does pH affect enzyme activity?
- What happens when all enzyme molecules are saturated with substrate?
- Give an example of how an inhibitor can affect enzyme function.
You’ve just added another powerful tool to your science toolkit! Understanding what affects enzyme activity helps you understand life at the cellular level—and you did it like a true scientist. Keep learning, keep growing, and never stop asking questions. Afrilearn is proud to be your learning companion. See you in the next lesson, champion!