Name Section Question 3 Most chemical reactions in biology take place on the surface of enzymes. Generally, such enzymes convert a substrate, or group of substrates, into a product, or set of products, that is crucial to the function of a cell. Below is a graph describing a general enzymatic reaction, in which the velocity of the chemical reaction is dependent upon the substrate concentration. a)On the graph below complete the following steps 1)Draw a solid line through the 5 reaction coordinates provided that best approximates the activity of a general single-subunit enzyme 2)Draw a dashed line parallel to the x-axis at the abscissa corresponding to Vmax 3)Find and label 1/2Vma 4)Find and label K 9.00E+03 三8.00E+03 7.00E+03 E5.00E+03 4.00E+03 3.00E+03 思2.00E+( 0.00E+01.00E-2.00E-3.00E-4.00E-5.00E-6.00E-7.00E b) what does the value of Km describe? c)The above graph only describes a specific enzymatic reaction at a single given concentration of the enzyme. Qualitatively, what would one expect to happen to vmax if the amount of d) Many enzymatic reactions can be broken down into 3 steps, each with its own specific rate substrate binding, catalysis, and product release. In most cases product release is not rate limiting and can therefore be disregarded with respect to its effect on the rate of the overall reaction. This leaves substrate binding and catalysis, each of which is modeled by a different portion of the above graph. Describe which section of the above graph best models the rate of catalysis and why? 7012Fall2003Name:___________________________________ Section:_____ 7.012 Fall 2003 Question 3 Most chemical reactions in biology take place on the surface of enzymes. Generally, such enzymes convert a substrate, or group of substrates, into a product, or set of products, that is crucial to the function of a cell. Below is a graph describing a general enzymatic reaction, in which the velocity of the chemical reaction is dependent upon the substrate concentration. a) On the graph below complete the following steps: 1) Draw a solid line through the 5 reaction coordinates provided that best approximates the activity of a general single-subunit enzyme. 2) Draw a dashed line parallel to the x-axis at the abscissa corresponding to Vmax. 3) Find and label 1/2 Vmax. 4) Find and label Km. 0.00E+00 1.00E+03 2.00E+03 3.00E+03 4.00E+03 5.00E+03 6.00E+03 7.00E+03 8.00E+03 9.00E+03 1.00E+04 0.00E+0 0 1.00E- 0 4 2.00E- 0 4 3.00E- 0 4 4.00E- 0 4 5.00E- 0 4 6.00E- 0 4 7.00E- 0 4 Substrate (M) Reaction Velocity (µmoles/min) b) What does the value of Km describe? c) The above graph only describes a specific enzymatic reaction at a single given concentration of the enzyme. Qualitatively, what would one expect to happen to Vmax if the amount of enzyme involved in the reaction were doubled? d) Many enzymatic reactions can be broken down into 3 steps, each with its own specific rate: substrate binding, catalysis, and product release. In most cases product release is not rate limiting and can therefore be disregarded with respect to its effect on the rate of the overall reaction. This leaves substrate binding and catalysis, each of which is modeled by a different portion of the above graph. Describe which section of the above graph best models the rate of catalysis and why?