a. Calculate the physiological DG of the reaction shown below at 37°C, as it occurs in the cytosol of neurons, with phosphocreatine at 4.7 mM, creatine at 1.0 mM, ADP at 0.73 mM, and ATP at 2.6 mM. The standard free energy change for the overall reaction is –12.5 kJ/mol. Phosphocreatine + ADP ® creatine + ATP
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.
1.
a. Calculate the physiological DG of the reaction shown below at 37°C, as it occurs in the cytosol of
neurons, with phosphocreatine at 4.7 mM, creatine at 1.0 mM, ADP at 0.73 mM, and ATP at 2.6
mM. The standard free energy change for the overall reaction is –12.5 kJ/mol.
Phosphocreatine + ADP ® creatine + ATP
b. The enzyme phosphoglucomutase catalyzes the conversion of glucose 1-phosphate to glucose
6-phosphate. Calculate the standard free energy change of this reaction if incubation of 20 mM
glucose 1-phosphate (no glucose-6 phosphate initially present) yields a final equilibrium mixture
of 1.0 mM glucose 1-phosphate and 19 mM glucose 6-phosphate at 25°C and pH 7.0.
c. If the rate of a nonenzymatic reaction is 1.2 x 10–2 μM s–1, what is the
the presence of an enzyme that reduces the activation energy by 30.5 kJ/mol?
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