To determine the Isoelectric point of a Protein, Isoelectric focusing

To determine the isoelectric point of a protein, first establish that a gel:

(a) Contains a denaturing detergent that can distribute uniform negative charges over the protein’s surface.
(b) Exhibits a stable pH gradient when ampholytes become distributed in an electric field.
(c) Is washed with an antibody specific to the protein of interest.
(d) Neutralizes all ionic groups on a protein by titrating them with strong bases.

The correct answer is:

(b) Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

Explanation:

To determine the isoelectric point (pI) of a protein, isoelectric focusing (IEF) is used. IEF relies on a stable pH gradient created by ampholytes (small charged molecules) in an electric field.

  • Proteins migrate within the gradient until they reach their isoelectric point (pI), where their net charge becomes zero and movement stops.
  • (a) Incorrect: SDS is used in SDS-PAGE, not IEF. It denatures proteins and applies a uniform negative charge, making pI determination impossible.
  • (c) Incorrect: Washing with antibodies is a step in Western blotting, not isoelectric focusing.
  • (d) Incorrect: Titrating ionic groups with strong bases does not determine pI; instead, proteins naturally stop moving at their pI in a stable pH gradient.

 

32 Comments
  • Shreeji Charan
    March 1, 2025

    🙋‍♀️

  • Prami Masih
    March 4, 2025

    👍👍

  • Anurag Giri
    August 14, 2025

    Ans b Exhibits a stable pH gradient when ampholytes become distributed in an electric field

  • Aman Choudhary
    August 14, 2025

    Option B is correct
    for determination of pi we need Ph gradient to stabilize the protein

  • Karishma Don
    August 14, 2025

    ampholytes creates a stable ph gradient in electric field

  • Khushi Agarwal
    August 14, 2025

    Option b is correct answer
    Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • Mansukh Kapoor
    August 14, 2025

    The correct answer is option 2nd
    Exhibits the stable pH gradient when ampholytes become disturbed in an electric field because at a point they stops migrating due to the isoelectric point

  • Dipti Sharma
    August 14, 2025

    (b) Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • Mohd juber Ali
    August 14, 2025

    Option (2) is right
    Exhibit the stable pH gradient when ampholytes become disturbed
    In low pH (+ve charge) protein move toward cathode electrod in pH strip (horizontal gel)
    pH = PI (static) neutral

  • Sneha Kumawat
    August 14, 2025

    The correct answer is B, exhibits a stable pH gradient when ampholytes become distributed in an electric field

  • Priya khandal
    August 14, 2025

    B is right

  • shruti sharma
    August 16, 2025

    b is right

  • Aafreen
    August 17, 2025

    Ans- b
    Proteins migrate within the gradient until they reach their isoelectric point (pI), where their net charge becomes zero and movement stops

  • Avni
    August 17, 2025

    (b) is correct

  • Bharti Yadav
    August 24, 2025

    Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • MOHIT AKHAND
    August 24, 2025

    Done sir ✅

  • Priyanka Choudhary
    August 24, 2025

    Answer b is correct answer,Exhibits a stable pH gradient when ampholytes become distributed in an electric field

  • Priya dhakad
    August 24, 2025

    Exhibits a stable pH gradient when ampholytes become distributed in an electric field. option b is correct.

  • Bhavana kankhedia
    August 24, 2025

    exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • Sonam Saini
    August 24, 2025

    Option B is right

  • Anjali
    August 24, 2025

    Ans is b

  • Sakshi
    August 24, 2025

    Option b is correct
    Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • Ankita Pareek
    August 24, 2025

    Exhibit a stable ph gradient when amhpholytes become distributed in an electric field

  • Falguni Prakash
    August 24, 2025

    2

  • sakshi khatri
    August 25, 2025

    done

  • Pratibha Jain
    August 30, 2025

    The correct answer is option (b)
    Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • Shriyanshi verma
    August 30, 2025

    Ans b Exhibits a stable pH gradient when ampholytes become distributed in an electric field

  • Sheikh Aleen
    August 30, 2025

    Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

  • Patel Radha
    August 30, 2025

    Done

  • Gayatri Nama
    August 30, 2025

    To determine the isoelectric point (PI) of a protein isoelectric focusing (IEF) is used . IEF relies on a stable pH gradient created by ampholytes electric field .
    Protein migrate with in the gradient untill they reach their isoelectric point ( PI) , where their net charge becomes zero and movement stops .

  • Shobha Kanwar
    August 31, 2025

    Option b is correct answer
    Exhibits a stable pH gradient when ampholytes become distributed in an electric field

  • Aakansha sharma Sharma
    October 1, 2025

    The correct answer is:

    (b) Exhibits a stable pH gradient when ampholytes become distributed in an electric field.

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