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    • Keywords


      Lysozyme; histidine modification; Micrococcus lysodeikticus; electrostatic potential in catalysis; pK-shifts

    • Abstract


      The literature data on the activity of histidine-15 modified hen egg white lysozyme are conflicting: the modified enzyme is reported to have more activity, similar activity or less activity by different authors. Amino acid analysis had shown modification of the single His-15. Detailed activity studies on His-15-modified (by iodoacetic acid or diethyl pyrocarbonate) lysozyme have shown that the contradicting reports are due to the specific choices of ionic strengths and cell wall substrate concentrations and can be attributed to the substrate being negatively charged. Our analysis suggests that even though histidine-15 is far removed from the active site of lysozyme, its chemical modification or binding of the negatively-charged substrate near it, changes the conformation around the active site. However, the change in the optimum activity on chemically modifying His-15 is small.

    • Author Affiliations


      Madhuri M Ugrankar1 G Krishnamoorthy1 Bala S Prabhananda1

      1. Chemical Physics Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Bombay - 400 005, India
    • Dates

  • Journal of Biosciences | News

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      Posted on July 25, 2019

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