What is the effect of substrate concentration on enzyme activity? How does enzyme activity change as substrate concentration decreases? Explain on a molecular basis.
I am not sure what the question wants from me. Would this be right, and is there anything missing from my response? :: As the substrate concentration increases, the rate of reaction also increases. it because if more substrate is available, then reactions will occur faster? I need some help wording this, please :)
yes, the reason is that there are more activation sites available for the enzyme to attach to and thus react with.
increasing rxn sites => increase rxn rate
opposite does the opposite of course
unfortunately that's all I can help with what I remember from memory
(I sold my bio book)
The effect of substrate concentration on enzyme activity is an important concept in enzymology. Enzymes are biological catalysts that speed up chemical reactions by binding to specific substrates. The rate of an enzymatic reaction is directly proportional to the substrate concentration until a maximum rate is reached, known as the enzyme's maximum velocity (Vmax).
So, to answer your question precisely, as substrate concentration decreases, enzyme activity decreases. This occurs because with fewer substrate molecules available, there is a reduced chance of them colliding with active sites on enzymes and forming enzyme-substrate complexes.
On a molecular basis, enzymes have active sites where substrates bind. The binding of a substrate to the active site induces structural changes in the enzyme, leading to the formation of an enzyme-substrate complex. This complex undergoes chemical reactions, resulting in the formation of products and the release of the enzyme.
At low substrate concentrations, enzymes may not encounter enough substrates to bind efficiently. Therefore, the rate of reaction will be slower. As substrate concentration increases, more active sites become occupied, and the reaction rate increases. However, once all the active sites are occupied, adding more substrate will have no further effect on the reaction rate because all the enzyme molecules are already engaged in catalysis.
To summarize, as substrate concentration decreases, enzyme activity decreases due to a limited number of substrate molecules available to bind to the enzyme's active sites. Conversely, as substrate concentration increases, enzyme activity increases until reaching Vmax, beyond which further increases in substrate concentration have no effect on the reaction rate.