An enzyme catalyzes a reaction in which substrateA is cleaved into two products, P and Q. In the catalytic mechanism, the enzyme converts A to a covalently-bound reaction intermediate X and product P, P then desorbs from the enzyme, and in a second chemical step, the enzyme converts the intermediate X in the EX complex to the final product Q (in EQ), which then desorbs from the enzyme E.You discover two inhibitors of this enzyme, I and J. I is a competitive inhibitor of the substrate A, and has nearly double the molecular weight of J. On the other hand, J is a mixed inhibitor of enzyme E, and its inhibitory effect on Km/ Vmax (the slope effect from the double reciprocal plot) is greater than that of 1 / Vmax (the intercept effect in a double reciprocal plot). That is Kis< Kii . At low pH, the conversion of EX to EQ is greatly slowed, kcat is decreased, and the intercept effect of inhibitor J is elevated, that is, the value of Kiiis diminished. When a high, fixed concentration of product P is added to the enzymatic reaction, the inhibition due to inhibitor I is unchanged, but inhibitor J becomes a competitive inhibitor vs. A. (1) To which enzyme forms do I and J bind? Explain how you got there. I cannot bind when A is at a concentration of infinity (no intercept effect). I is competitive vs. A and therefore binds to E. I may structurally resemble substrate A. J is a mixed inhibitor; it exerts both a slope effect and an intercept effect, but the slope effect is more significant than the intercept effect: Kis< Kii. J probably binds to E twice: to E to form EJ, which gives rise to the slope effect, and the intercept effects comes from binding to EA, or a downstream complex such as EXP, EX, or EQ. J has structural features similar to I, whichis why it can bind to E, but is smaller than I and can fit into another pocket during catalysis.
Enzyme kinetics
In biochemistry, enzymes are proteins that act as biological catalysts. Catalysis is the addition of a catalyst to a chemical reaction to speed up the pace of the reaction. Catalysis can be categorized as either homogeneous or heterogeneous, depending on whether the catalysts are distributed in the same phase as that of the reactants. Enzymes are an essential part of the cell because, without them, many organic processes would slow down and thus will affect the processes that are important for cell survival and sustenance.
Regulation of Enzymes
A substance that acts as a catalyst to regulate the reaction rate in the living organism's metabolic pathways without itself getting altered is an enzyme. Most of the biological reactions and metabolic pathways in the living systems are carried out by enzymes. They are specific for their works and work in particular conditions. It maintains the best possible rate of reaction in the most stable state. The enzymes have distinct properties as they can proceed with the reaction in any direction, their particular binding sites, pH specificity, temperature specificity required in very few amounts.
An enzyme catalyzes a reaction in which substrateA is cleaved into two products, P and Q. In the catalytic mechanism, the enzyme converts A to a covalently-bound reaction intermediate X and product P, P then desorbs from the enzyme, and in a second chemical step, the enzyme converts the intermediate X in the EX complex to the final product Q (in EQ), which then desorbs from the enzyme E.You discover two inhibitors of this enzyme, I and J. I is a competitive inhibitor of the substrate A, and has nearly double the molecular weight of J. On the other hand, J is a mixed inhibitor of enzyme E, and its inhibitory effect on Km/ Vmax (the slope effect from the double reciprocal plot) is greater than that of 1 / Vmax (the intercept effect in a double reciprocal plot). That is Kis< Kii .
At low pH, the conversion of EX to EQ is greatly slowed, kcat is decreased, and the intercept effect of inhibitor J is elevated, that is, the value of Kiiis diminished.
When a high, fixed concentration of product P is added to the enzymatic reaction, the inhibition due to inhibitor I is unchanged, but inhibitor J becomes a competitive inhibitor vs. A.
(1) To which enzyme forms do I and J bind? Explain how you got there.
I cannot bind when A is at a concentration of infinity (no intercept effect). I is competitive vs. A and therefore binds to E. I may structurally resemble substrate A.
J is a mixed inhibitor; it exerts both a slope effect and an intercept effect, but the slope effect is more significant than the intercept effect: Kis< Kii.
J probably binds to E twice: to E to form EJ, which gives rise to the slope effect, and the intercept effects comes from binding to EA, or a downstream complex such as EXP, EX, or EQ. J has structural features similar to I, whichis why it can bind to E, but is smaller than I and can fit into another pocket during catalysis.
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