Topic 4 chapter 5 part 3 enzymes - limiting factors
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This document discusses limiting factors in enzyme activity. It provides two examples: 1) As substrate concentration increases, the reaction rate increases until all enzyme sites are occupied. Then the substrate becomes the limiting factor. 2) Doubling the enzyme concentration doubles the reaction rate. Beyond the point where all substrate is bound, the enzyme becomes the limiting factor. The key points are that a limiting factor is the component that determines the reaction rate, and this can change from substrate to enzyme depending on their relative concentrations.
![Example 1
• Independent Variable: Substrate concentration
• LIMITING FACTOR IS Substrate concentration
From 0 to Point XFrom 0 to Point X
Description Explanation
As the [substrate] increases,
the rate of reaction increases
until Point X when rate of
reaction reaches its maximum.
At any [substrate] before Point
X, there are more enzyme
molecules than substrate
molecules
At Point X, all the enzyme
active sites are occupied by
substrate molecules](https://image.slidesharecdn.com/topic4chapter5part3-enzymes-limitingfactors-130814060549-phpapp02/85/Topic-4-chapter-5-part-3-enzymes-limiting-factors-5-320.jpg)
![Example 1
• Independent Variable: Substrate concentration
• LIMITING FACTOR IS Enzyme concentration
Beyond Point XBeyond Point X
Description Explanation
Graph remains constant
/ becomes a plateau
after Point X.
Maximum rate of
reaction
After point X, the rate of reaction does not
increase even when [substrate] increases.
This is because all the enzyme molecule’s
active sites are being occupied at any one
time. That is, all the enzyme molecules
are saturated.
Amount of products formed per unit time
remains constant](https://image.slidesharecdn.com/topic4chapter5part3-enzymes-limitingfactors-130814060549-phpapp02/85/Topic-4-chapter-5-part-3-enzymes-limiting-factors-6-320.jpg)
![Example 2
• Independent Variable: Substrate concentration
From 0 to Point YFrom 0 to Point Y
Description Explanation
Rate of reaction
increases as [Substrate]
increases for both
Graphs A and B.
At any [Substrate] before Point Y, there
are more enzymes than substrate
molecules.
At Point X, all the enzyme active sites are
occupied by substrate molecules
Rate of reaction of (B) is
double that of (A)
There are double the number of enzyme
molecules in (B). Double the frequency of
collision between Enzyme and Substrate
molecules in (B)
LIMITING FACTOR Substrate Concentration](https://image.slidesharecdn.com/topic4chapter5part3-enzymes-limitingfactors-130814060549-phpapp02/85/Topic-4-chapter-5-part-3-enzymes-limiting-factors-8-320.jpg)
![Example 2
• Independent Variable: Enzyme concentration
Beyond Point YBeyond Point Y
LIMITING FACTOR Enzyme Concentration
Description Explanation
Graph remains
constant /
becomes a
plateau after
Point X.
Maximum rate
of reaction
After point X, the rate of reaction does not increase
even when [substrate] increases.
This is because all the enzyme molecule’s active sites
are being occupied at any one time. That is, all the
enzyme molecules are saturated.
Amount of products formed per unit time remains
constant
Rate of reaction
of (B) is double
that of (A)
Double the number of enzyme molecules in (B).
Double the number of E-S complex formed per unit
time. Therefore, double the amount of products
formed](https://image.slidesharecdn.com/topic4chapter5part3-enzymes-limitingfactors-130814060549-phpapp02/85/Topic-4-chapter-5-part-3-enzymes-limiting-factors-9-320.jpg)
![Example 2
• Independent Variable: Enzyme concentration
Beyond Point YBeyond Point Y
LIMITING FACTOR Enzyme Concentration
Description Explanation
Graph remains
constant /
becomes a
plateau after
Point X.
Maximum rate
of reaction
After point X, the rate of reaction does not increase
even when [substrate] increases.
This is because all the enzyme molecule’s active sites
are being occupied at any one time. That is, all the
enzyme molecules are saturated.
Amount of products formed per unit time remains
constant
Rate of reaction
of (B) is double
that of (A)
Double the number of enzyme molecules in (B).
Double the number of E-S complex formed per unit
time. Therefore, double the amount of products
formed](https://image.slidesharecdn.com/topic4chapter5part3-enzymes-limitingfactors-130814060549-phpapp02/85/Topic-4-chapter-5-part-3-enzymes-limiting-factors-10-320.jpg)
Topic 4 chapter 5 part 3 enzymes - limiting factors
- 1. Topic 4: Chapter 5 EnzymesEnzymes –– Part 3Part 3 Limiting Factors Limiting Factors
- 2. What is a limiting factor? Any factor that directly affects the rate of reaction at which a process occurs if its quantity is changed The value of this factor has to be increased in order to increase the rate of the process
- 3. Factors affecting enzyme activity 1) Temperature 2) pH 3) Substrate Concentration 4) Enzyme Concentration
- 5. Example 1 • Independent Variable: Substrate concentration • LIMITING FACTOR IS Substrate concentration From 0 to Point XFrom 0 to Point X Description Explanation As the [substrate] increases, the rate of reaction increases until Point X when rate of reaction reaches its maximum. At any [substrate] before Point X, there are more enzyme molecules than substrate molecules At Point X, all the enzyme active sites are occupied by substrate molecules
- 6. Example 1 • Independent Variable: Substrate concentration • LIMITING FACTOR IS Enzyme concentration Beyond Point XBeyond Point X Description Explanation Graph remains constant / becomes a plateau after Point X. Maximum rate of reaction After point X, the rate of reaction does not increase even when [substrate] increases. This is because all the enzyme molecule’s active sites are being occupied at any one time. That is, all the enzyme molecules are saturated. Amount of products formed per unit time remains constant
- 7. Example 2 0.4moldm-3 Enzyme 0.2moldm-3 Enzyme RateofReaction Substrate Concentration / Arbitrary Units (A) (B) X Y
- 8. Example 2 • Independent Variable: Substrate concentration From 0 to Point YFrom 0 to Point Y Description Explanation Rate of reaction increases as [Substrate] increases for both Graphs A and B. At any [Substrate] before Point Y, there are more enzymes than substrate molecules. At Point X, all the enzyme active sites are occupied by substrate molecules Rate of reaction of (B) is double that of (A) There are double the number of enzyme molecules in (B). Double the frequency of collision between Enzyme and Substrate molecules in (B) LIMITING FACTOR Substrate Concentration
- 9. Example 2 • Independent Variable: Enzyme concentration Beyond Point YBeyond Point Y LIMITING FACTOR Enzyme Concentration Description Explanation Graph remains constant / becomes a plateau after Point X. Maximum rate of reaction After point X, the rate of reaction does not increase even when [substrate] increases. This is because all the enzyme molecule’s active sites are being occupied at any one time. That is, all the enzyme molecules are saturated. Amount of products formed per unit time remains constant Rate of reaction of (B) is double that of (A) Double the number of enzyme molecules in (B). Double the number of E-S complex formed per unit time. Therefore, double the amount of products formed
- 10. Example 2 • Independent Variable: Enzyme concentration Beyond Point YBeyond Point Y LIMITING FACTOR Enzyme Concentration Description Explanation Graph remains constant / becomes a plateau after Point X. Maximum rate of reaction After point X, the rate of reaction does not increase even when [substrate] increases. This is because all the enzyme molecule’s active sites are being occupied at any one time. That is, all the enzyme molecules are saturated. Amount of products formed per unit time remains constant Rate of reaction of (B) is double that of (A) Double the number of enzyme molecules in (B). Double the number of E-S complex formed per unit time. Therefore, double the amount of products formed