The dissociation constant, Kd for a complex between protein A and protein B is 4.1 μM. If the two proteins are mixed together at initial concentrations of [A]= 0.025 μM and [B] = 4.7 μM, calculate (a) the equilibrium concentrations of A, B, and AB (the dimer formed by A and B) (b) the percentage of A bound to B
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.
The dissociation constant, Kd for a complex between protein A and protein B is 4.1 μM. If the two proteins are mixed together at initial concentrations of [A]= 0.025 μM and [B] = 4.7 μM, calculate (a) the equilibrium concentrations of A, B, and AB (the dimer formed by A and B) (b) the percentage of A bound to B
The equilibrium association between proteins A & B to form AB and the dissociation of AB to give A & B can be represented as shown below.
Here Ka is the equilibrium association constant and Kd is the equilibrium dissociation constant.
Here we introduce 0.025 of A and 4.7 of B. These two begin to bind with each other and proceed towards reaching equilibrium. Hence the concentration of A and B starts to decrease , while the concentration of AB increases. Once equilibrium is reached, the rate of association of A & B to form AB becomes equal to the rate of dissociation of AB to A & B. Hence once equilibrium is reached, the concentrations of A , B and AB does not change any further. The concentrations of A , B and AB at equilibrium are [A]eq , [B]eq and [AB]eq respectively.
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