- Recognise the properties of enzyme and its roles in metabolism.
- Explain enzyme specificity in terms of active site.
Properties of enzyme
👆🏻This photo showing the properties of enzyme.
1. Enzyme with catalytic property
- Enzyme having remarkable catalytic power.
- A small amount of enzyme is already enough for catalysing reaction.
- Enzyme remain unchanged throughout the reaction.
2. Enzyme with specificity
- Enzyme having a specific action that it only acts on a particular substrate and reaction.
3. Enzyme with reversibility
- Enzyme catalysed reactions are reversible and some are not reversible.
- Enzyme can be reused that a small amount of enzyme is required for each of the reaction.
4. Enzyme is sensitive to heat
- Enzyme is extremely sensitive to heat that enzyme work best in optimal temperature.
- Enzyme will be inactive at low temperature.
- Enzyme will be denatured at high temperature.
5. Enzyme is sensitive to pH
- Enzyme is extremely sensitive to heat that enzyme work best in optimal pH.
- Enzyme will be inactive or denatured if not in their optimal pH.
Role of enzyme in metabolism
In HKDSE Biology examination, you will be used to draw this graph indicating the effect of the enzyme towards activation energy of metabolism ❗️ ❕
👆🏻This photo comparing the difference in activation energy of having catalyst - enzyme or without it.
- Enzyme speed up metabolism through lowering the activation energy.
- Enzyme act as a important catalyse in metabolism .
Active site of enzyme
👆🏻This photo showing how substrate binds to active site of enzyme.
- Active site ➡️where the substrate binds to enzyme.
- Amino acid in active sites having different side chain with different properties like acidic, alkaline, hydrophilic or hydrophobic.
- only specific substrate that can bind to the active site of enzyme and undergo chemical reaction.l
- 🔺 The specificity of enzyme is due to the active site of enzyme.
👆🏻Lock and Key hypothesis is commonly used to explain the specificity of enzyme.
🤗 Substrate is like the key while enzyme is like the lock that only a particular key can open a lock like only particular substrate can bind to enzyme and form enzyme-substrate complex.
That's the end of this topic 👏🏻
References
- mukoshi, J., & Ebc. (n.d.). Easy Biology Class. Retrieved from https://www.easybiologyclass.com/properties-of-enzymes-biochemistry-lecture-notes/
- Enzymes: Properties and Mechanism of Enzyme Action. (2015, August 27). Retrieved from http://www.biologydiscussion.com/enzymes/enzymes-properties-and-mechanism-of-enzyme-action/6145