First, you apply a signaling ligand known to activate this Gs protein and track yellow fluorescence. Second, you apply the signaling ligand and the purified bacterial toxin simultaneously and track yellow fluorescence. Which of the following conclusion will you draw based on the above experimental data? The toxin locks the α subunit in the “off” state. It is impossible to draw conclusions from these data. The toxin locks the α subunit in the “on” state. The toxin has no effect on heterotrimeric G-protein signaling.
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.
You have isolated a new species of infectious bacteria. The bacterium releases a toxin that you believe is adversely affecting heterotrimeric Gs (stimulatory)-protein-based signaling. To explore this hypothesis you use an epithelial cell line that is expressing a cyan fluorescent protein (CFP)-labeled α subunit and a yellow fluorescent protein (YFP)-labeled β subunit of a heterotrimeric Gs-protein. CFP emits blue light and has excitation and emission wavelengths of 440 nm and 490 nm, respectively. YFP emits yellow light and has excitation and emission wavelengths of 490 nm and 527 nm, respectively. To test your hypothesis, you perform two experiments. First, you apply a signaling ligand known to activate this Gs protein and track yellow fluorescence. Second, you apply the signaling ligand and the purified bacterial toxin simultaneously and track yellow fluorescence. Which of the following conclusion will you draw based on the above experimental data?
- The toxin locks the α subunit in the “off” state.
- It is impossible to draw conclusions from these data.
- The toxin locks the α subunit in the “on” state.
- The toxin has no effect on heterotrimeric G-protein signaling.
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