An enzyme with an unknown reaction mechanism has been isolated and is being investigated in the lab. Based on the information given below, propose one or more specific catalytic strategies (covalent, acid-base, and/or metal ion catalysis) used by the enzyme and predict the role of each catalytic residue in the enzyme's reaction cycle. Explain your reasoning. (a) Mapping of the active site with substrate analog showed that it contains a critical Ser residue. (b) Studies conducted in buffers of varying pH showed that the enzyme is sensitive to pH changes and has two catalytically important residues with pKa values of ~10.5 and ~4.0. (c) Substitution of the Ser residue with Ala resulted in a five-fold increase in the KM but had no effect on the kcat. (d) The reaction rate was insensitive to the addition of metal chelators such as EDTA and EGTA.
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 with an unknown reaction mechanism has been isolated and is being investigated in the lab. Based on the information given below, propose one or more specific catalytic strategies (covalent, acid-base, and/or metal ion catalysis) used by the enzyme and predict the role of each catalytic residue in the enzyme's reaction cycle. Explain your reasoning. (a) Mapping of the active site with substrate analog showed that it contains a critical Ser residue. (b) Studies conducted in buffers of varying pH showed that the enzyme is sensitive to pH changes and has two catalytically important residues with pKa values of ~10.5 and ~4.0. (c) Substitution of the Ser residue with Ala resulted in a five-fold increase in the KM but had no effect on the kcat. (d) The reaction rate was insensitive to the addition of metal chelators such as EDTA and EGTA.
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