What are the amino acids of the catalytic triad of chymotrypsin? State the mode catalysis shown by each of the amino acids that you have named. Predict what will happen if aspartic acid of the triad is replaced by asparagine.
Q: , non-ionizable R groups.
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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.
Step by step
Solved in 2 steps
- Chymotrypsin, trypsin, and elastase all share the same catalytic mechanism, but have different specificities. (a) These proteases are considered serine proteases because the active sites contain serine, histidine and aspartate. Describe the roles that each of these amino acid residues play in hydrolyzing protein substrates. (b) The active site pockets of chymotrypsin, trypsin, and elastase are shown in the image below. Based on the image, which side chain of the amino acids would they prefer to cleave respectively, Ala, Arg, or Trp? Explain your answers. Val 216 Val 190 Asp 189 Chymotrypsin Trypsin ElastaseChymotrypsin, trypsin, and elastase all share the same catalytic mechanism, but have different specificities. (a) These proteases are considered serine proteases because the active sites contain serine, histidine and aspartate. Describe the roles that each of these amino acid residues play in hydrolyzing protein substrates. (b) The active site pockets of chymotrypsin, trypsin, and elastase are shown in the image below. Based on the image, which side chain of the amino acids would they prefer to cleave respectively, Ala, Arg, or Trp? Explain your answers. Val 216KVal 190 Asp 189 Chymotrypsin Trypsin ElastaseThe catalytic efficiency of many enzymes depends on pH. Chymotrypsin, which has a well-known catalytic mechanism, shows a maximum value of kcat/Km at pH 8.0. A) Draw a pH curve of chymotrypsin activity over the pH range of 5 to 10 and briefly explain the rationale within the context of catalysis for your depiction. In particular, note how kcat and Km may change over this pH range. B) Enzymes of the a-amylase family catalyze a reaction by forming a covalent intermediate analogous to chymotrypsin, but to a conserved aspartate residue. Illustrate a catalytic mechanism containing a tetrahedral intermediate for a glycogen debranching enzyme based upon its potential membership in the a-amylase family. (don’t need to draw a whole glycogen)
- (i) Describe the mechanism of chymotrypsin in cleaving a peptide bond, highlighting the roles of the catalytice triad for the two phases of the catalytic reactions. Explain the significance of the oxyanion hole for the catalysis. (ii) All serine proteases contain the catalytic triad and these amino acids are positioned in the exact same conformation. Since this is true, why do trypsin and chymotrypsin have such different substrate specificity? What features of the enzyme allow for this situation?You are studying the kinetics of a novel competitive inhibitor of ATP-citrate lyase that can be used to prevent obesity. What is likely true about this inhibitor? (A) This inhibitor lowers the Vmax of ATP-citrate lyase. (B) The inhibitor likely looks structurally similar to acetyl CoA. (C) The inhibitor binds to an allosteric region on ATP-citrate lyase and prevents catalysis. (D) You can distinguish between an uninhibited and inhibited enzyme by comparing the x-intercepts on a Lineweaver-Burk plot. (E) This inhibitor lowers the KM of ATP-citrate lyase. Related to this question, you should also be able to: • explain the function of ATP-citrate lyase and why inhibition would prevent obesity • interpret Michaelis-Menten & Lineweaver-Burk plots related to this question • explain the differences between a competitive and non-competitive inhibitorHow would chymotrypsin's catalytic triad be affected by extremely low and extremely high pH values (assuming the rest of the protein remains intact)?
- Beginning with the 1st tetrahedral intermediate, show the complete steps in chymotrypsin mechanism that occurs to form the 2nd chymotrypsin intermediate in the chymotrypsin active site. The substrate for chymotrypsin to be used is Ala-Tyr-Gly. Further, name the amino acid(s) that would be released as a result of the reactions you'd illustrated above.You have discovered a new enzyme that has a nearly identical active site to chymotrypsin. This new enzyme uses the same catalytic triad and the same reaction mechanism as chymotrypsin. Your new enzyme differs from chymotrypsin because it cuts peptides at the C terminus of polar, non-ionizable R groups. a) Beginning with the first tetrahedral intermediate, draw the mechanism of catalysis that occurs to cleave the tripeptide Asn-Phe-Lys substrate ending your answer with product and free enzyme. b) From the list below, which of the components would most likely be found in the area of the enzyme that substitutes the hydrophobic pocket of chymotrypsin? Very briefly explain your choice(s)., Ser lle Zn Val c) You've constructed a molecule that is able to bind to the 1 tetrahedral intermediate of your new.enzyme, preventing catalysis. From experimental results, you can see that this molecule is only able to bind to the tetrahedral intermediate. Assuming that this enzyme follows…You have discovered a new enzyme that has a nearly identical active site to chymotrypsin. This new enzyme uses the same catalytic triad and the same reaction mechanism as chymotrypsin. Your new enzyme differs from chymotrypsin because it cuts peptides at the C terminus of polar, non- ionizable R groups.A) Beginning with the first tetrahedral intermediate, draw the mechanism of catalysis that occurs to cleave the tripeptide Asn- Phe- Lys substrate ending your answer with the product and free enzyme.
- You have discovered a new enzyme that has a nearly identical active site to chymotrypsin. This new enzyme uses the same catalytic triad and the same reaction mechanism as chymotrypsin. Your new enzyme differs from chymotrypsin because it cuts peptides at the C terminus of polar, non- ionizable R groups. A) Beginning with the first tetrahedral intermediate, draw the mechanism of catalysis that occurs to cleave the tripeptide Asn- Phe- Lys substrate ending your answer with the product and free enzyme. B) From the list below, which of the components would most likely be found in the area of the enzyme that substitutes the hydrophobic pocket of chymotrypsin? Very briefly explain your choice(s): Ser ile Zn+ Val C) You've constructed a molecule that is able to bind to the 1st tetrahedral intermediate of your new enzyme, preventing catalysis. From experimental results, you can see that this molecule is only able to bind to the tetrahedral intermediate. Assuming that this enzyme follows…Draw a schematic illustration of the hydrolysis of N-acetylphenylalaninamide catalyzed byalpha-chymotrypsin in which you indicate the important catalytic residues in the active site and how thesubstrate undergoes transformation to products through two different tetrahedral intermediates.In the first step of the aldolase reaction, an active site Lys229 residue, with its side chain amino group in the deprotonated state, acts as a nucleophile and attacks the carbonyl C2 carbon of fructose 1,6-bisphosphate to form a Schiff base (boxed in the scheme). Since the pKa of the Lys side chain amino group in free solution is ~10.5, the pKa of Lys229 side chain must have been perturbed to a (higher lower) value for the enzyme to be active at neutral pH. the answer should include sufficient details, including the definition of pKa.