IIT JAM Exam > IIT JAM Questions > Lysozyme has optimal activity at a pH centere...
Start Learning for Free
Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?
- a)The glutamic acid residue is in a more polar environment than the aspartic acid.
- b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.
- c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.
- d)The glutamic acid residue acts as a general base catalyst.
Correct answer is option 'C'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Verified Answer
Lysozyme has optimal activity at a pH centered around pH 5.0. The acti...
The catalytic mechanism of lysozyme involves both general acid and general base catalysis. Glu 35 participates in general acid catalysis (donates a proton) and Asp 52 participates in general base catalysis (stabilising the positive charge of the oxonium ion). During the entire catalytic mechanism, the aspartic acid residue remains unprotonated. Its because pH 5 is more than the pKa = 4.0 of aspartic acid.
Most Upvoted Answer
Lysozyme has optimal activity at a pH centered around pH 5.0. The acti...
Explanation:
The correct answer is option C. During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.
Explanation:
Lysozyme is an enzyme that catalyzes the hydrolysis of the β-1,4-glycosidic bond between N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) in the peptidoglycan layer of bacterial cell walls. The optimal activity of lysozyme is centered around pH 5.0, which suggests that the active site of the enzyme is most efficient at this pH.
Role of Glutamic Acid and Aspartic Acid Residues:
The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). These residues play important roles in the catalytic mechanism of lysozyme.
1. Glutamic Acid Residue:
The glutamic acid residue in the active site of lysozyme acts as a general acid catalyst. It donates a proton to the glycosidic oxygen of the substrate, facilitating the cleavage of the bond between NAM and NAG. The pKa of glutamic acid is 5.5, which means that it is predominantly protonated at pH 5.0, the optimal pH for lysozyme activity.
2. Aspartic Acid Residue:
The aspartic acid residue in the active site of lysozyme plays a different role. It stabilizes the oxonium ion transition state that forms during the catalytic mechanism. The pKa of aspartic acid is 4.0, which means that it is predominantly protonated at pH 5.0. The protonated form of aspartic acid has a negatively charged carboxylate group, which can interact with the developing positive charge on the oxonium ion transition state, stabilizing it.
Stabilization of the Oxonium Transition State:
During the catalytic mechanism of lysozyme, the cleavage of the β-1,4-glycosidic bond between NAM and NAG leads to the formation of an oxonium ion transition state. This transition state is highly unstable and requires stabilization for the reaction to proceed. The aspartic acid residue in the active site of lysozyme stabilizes this transition state by interacting with the developing positive charge on the oxonium ion.
Therefore, the correct statement is that during the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid (option C). The other statements are not correct because the aspartic acid residue does not remain protonated throughout the entire catalytic mechanism (option B) and the glutamic acid residue does not act as a general base catalyst (option D). The relative polarity of the glutamic acid and aspartic acid residues in the active site cannot be determined solely based on their pKa values (option A).
The correct answer is option C. During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.
Explanation:
Lysozyme is an enzyme that catalyzes the hydrolysis of the β-1,4-glycosidic bond between N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) in the peptidoglycan layer of bacterial cell walls. The optimal activity of lysozyme is centered around pH 5.0, which suggests that the active site of the enzyme is most efficient at this pH.
Role of Glutamic Acid and Aspartic Acid Residues:
The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). These residues play important roles in the catalytic mechanism of lysozyme.
1. Glutamic Acid Residue:
The glutamic acid residue in the active site of lysozyme acts as a general acid catalyst. It donates a proton to the glycosidic oxygen of the substrate, facilitating the cleavage of the bond between NAM and NAG. The pKa of glutamic acid is 5.5, which means that it is predominantly protonated at pH 5.0, the optimal pH for lysozyme activity.
2. Aspartic Acid Residue:
The aspartic acid residue in the active site of lysozyme plays a different role. It stabilizes the oxonium ion transition state that forms during the catalytic mechanism. The pKa of aspartic acid is 4.0, which means that it is predominantly protonated at pH 5.0. The protonated form of aspartic acid has a negatively charged carboxylate group, which can interact with the developing positive charge on the oxonium ion transition state, stabilizing it.
Stabilization of the Oxonium Transition State:
During the catalytic mechanism of lysozyme, the cleavage of the β-1,4-glycosidic bond between NAM and NAG leads to the formation of an oxonium ion transition state. This transition state is highly unstable and requires stabilization for the reaction to proceed. The aspartic acid residue in the active site of lysozyme stabilizes this transition state by interacting with the developing positive charge on the oxonium ion.
Therefore, the correct statement is that during the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid (option C). The other statements are not correct because the aspartic acid residue does not remain protonated throughout the entire catalytic mechanism (option B) and the glutamic acid residue does not act as a general base catalyst (option D). The relative polarity of the glutamic acid and aspartic acid residues in the active site cannot be determined solely based on their pKa values (option A).
|
Explore Courses for IIT JAM exam
|
|
Similar IIT JAM Doubts
Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer?
Question Description
Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? for IIT JAM 2024 is part of IIT JAM preparation. The Question and answers have been prepared according to the IIT JAM exam syllabus. Information about Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for IIT JAM 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer?.
Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? for IIT JAM 2024 is part of IIT JAM preparation. The Question and answers have been prepared according to the IIT JAM exam syllabus. Information about Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for IIT JAM 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer?.
Solutions for Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for IIT JAM.
Download more important topics, notes, lectures and mock test series for IIT JAM Exam by signing up for free.
Here you can find the meaning of Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer?, a detailed solution for Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? has been provided alongside types of Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Lysozyme has optimal activity at a pH centered around pH 5.0. The active site of lysozyme contains a glutamic acid residue (pKa = 5.5) and an aspartic acid residue (pKa = 4.0). Which of the following statements is correct about the mechanism of lysozyme?a)The glutamic acid residue is in a more polar environment than the aspartic acid.b)During the entire catalytic mechanism, the aspartic acid residue remains protonated.c)During the mechanism, an oxonium transition state forms, which is stabilized by aspartic acid.d)The glutamic acid residue acts as a general base catalyst.Correct answer is option 'C'. Can you explain this answer? tests, examples and also practice IIT JAM tests.
|
|
Explore Courses for IIT JAM exam
|
|
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup