What is the effect of substrate concentration on enzyme activity? How does enzyme activity change as substrate concentration decreases? Explain your observations by discussing this reaction on a molecular level.
Since this is not my area of expertise, I searched Google under the key words "'substrate concentration' enzyme" to get these possible sources:
http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/notes/chpt8/factorssubstrconc.htm
http://www.worthington-biochem.com/introbiochem/substrateConc.html
http://student.ccbcmd.edu/~gkaiser/biotutorials/proteins/enzyme.html
http://www.chemsoc.org/networks/learnnet/cfb/enzymes.htm
(Broken Link Removed)
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.
The effect of substrate concentration on enzyme activity is often described by the Michaelis-Menten equation. At low substrate concentrations, the rate of enzyme activity is directly proportional to the substrate concentration. As the substrate concentration increases, the rate of enzyme activity initially increases until it reaches a maximum called the maximum velocity (Vmax). This occurs because all active sites on the enzyme molecules are occupied by the substrate, and the enzyme is working at its maximum capacity.
However, when the substrate concentration exceeds a certain point, known as the saturation point, the enzyme activity levels off or becomes constant. At this point, all the enzyme's active sites are occupied, and adding more substrate does not increase the enzyme activity further.
When the substrate concentration decreases, the enzyme activity decreases because there are fewer substrate molecules available to bind to the enzyme's active sites. This means fewer enzyme-substrate complexes can form, leading to a reduction in the rate of product formation.
On a molecular level, enzymes catalyze reactions by binding to the substrate at specific regions called active sites. The active site has a unique shape that complements the shape of the substrate molecules. As substrate molecules bind to the active sites, they undergo a series of chemical reactions to form products.
At low substrate concentrations, there are many available active sites on the enzyme, and substrates can easily bind to these sites, leading to a high rate of enzyme activity. As the substrate concentration decreases, there are fewer available substrate molecules to bind to the active sites. This can lead to slower reaction rates as fewer enzyme-substrate complexes are formed.
Overall, the effect of substrate concentration on enzyme activity is dependent on the availability of substrate molecules to bind to the enzyme's active sites. Higher substrate concentrations generally lead to increased enzyme activity until a saturation point is reached, while lower substrate concentrations result in decreased enzyme activity due to fewer substrate molecules available for binding.
The effect of substrate concentration on enzyme activity is typically described by the Michaelis-Menten kinetics. At low substrate concentrations, the rate of an enzymatic reaction is directly proportional to the substrate concentration because there are plenty of enzymes available to bind with the substrate. As the substrate concentration increases, the enzyme active sites become saturated, and the rate of the reaction reaches a maximum, known as the maximum velocity (Vmax).
When the substrate concentration decreases, the enzyme activity also decreases. This happens because at low substrate concentrations, fewer enzyme-substrate complexes are formed, leading to a lower rate of catalysis. Additionally, as the substrate concentration decreases, the chances of collision between the enzyme and the substrate decrease, reducing the likelihood of successful enzyme-substrate binding.
On a molecular level, enzyme activity is reliant on the formation of an enzyme-substrate complex. The active site of an enzyme, which is a specific region on the enzyme where the substrate binds, undergoes a conformational change upon substrate binding. This conformational change enables the enzyme to catalyze the conversion of the substrate into product.
As the substrate concentration decreases, there are fewer substrate molecules available to bind with the enzyme's active sites. Consequently, there is a lower probability of successful collisions between the enzyme and substrate molecules, resulting in a decrease in enzyme activity. With fewer enzyme-substrate complexes being formed, the rate of the reaction decreases.
It's important to note that the relationship between substrate concentration and enzyme activity is not linear but follows a hyperbolic curve. This is because as the substrate concentration approaches infinity, the enzyme active sites become saturated, and the reaction rate approaches its maximum velocity (Vmax).