Enzyme Science Miscellaneous

Enzyme Science Miscellaneous

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Enzyme Science

Enzyme Science Miscellaneous
  1. In an assay of the type II dehydroquinase of molecular mass 18 kDa, it is found that the Vmax of the enzyme is 0.0134 µmol.min–1 when 1.8 µg enzyme is added to the assay mixture. If the Km for the substrate is 25 µM, the kcat/Km ratio will be _____ ×104 M–1.s–1.








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    NA

    Correct Option: D

    NA

  1. Choose the CORRECT combination of True (T) and False (F) statements about microcarriers used in animal cell culture.
    P. Higher cell densities can be achieved using microcarriers
    Q. Microcarriers increase the surface area for cell growth
    R. Microcarriers are used for both anchorage- and nonanchorage-dependent cells
    S. Absence of surface charge on microcarriers enhances attachment of cells








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    NA

    Correct Option: B

    NA

  1. Which one of the following statements is NOT true?








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    NA

    Correct Option: C

    NA

Direction: An aliquot of competent E. coli cells were used for determination of cell density by plate count method and another aliquot was used for transformation by plasmid DNA

  1. E. coli cell culture (1 ml) was diluted 1:1000000 and 200µl of this was used for plating. After 12h incubation of the plate, the number of colony forming units (CFU) was 150. What is the total CFUper ml in original culture ?








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    Since, 1 ml = 1000 µl
    New volume = 10³ × 106 µl = 109 µl.
    Since, only 200 µl is used we have a dilution factor of

    =
    108 μl
    		 = 0.5 × 107
    200 μl

    Number of colony in original one ml culture would be
    = 0.5 × 107 × 150
    = 7.5 × 108.

    Correct Option: A

    Since, 1 ml = 1000 µl
    New volume = 10³ × 106 µl = 109 µl.
    Since, only 200 µl is used we have a dilution factor of

    =
    108 μl
    		 = 0.5 × 107
    200 μl

    Number of colony in original one ml culture would be
    = 0.5 × 107 × 150
    = 7.5 × 108.

  1. The following cross-linking agents may be used for the immobilization of enzymes








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    Commonly used methods for the covalent immobilisation of enzymes includes activation of Sepharose by cyanogen bromide. Conditions are chosen to minimise the formation of the inert carbamate. Glutaraldehyde is used to cross-link enzymes or link them to supports. It usually consists of an equilibrium mixture of monomer and oligomers. The product of the condensation of enzyme and glutaraldehyde may be stabilised against dissociation by reduction with sodium borohydride.

    Correct Option: D

    Commonly used methods for the covalent immobilisation of enzymes includes activation of Sepharose by cyanogen bromide. Conditions are chosen to minimise the formation of the inert carbamate. Glutaraldehyde is used to cross-link enzymes or link them to supports. It usually consists of an equilibrium mixture of monomer and oligomers. The product of the condensation of enzyme and glutaraldehyde may be stabilised against dissociation by reduction with sodium borohydride.