• Difference spectroscopic studies on binding of Cibacron blue F3GA to ribosome inactivating proteins: Effect of β-mercaptoethanol on the interaction with ricin

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    • Keywords


      Ribosome inactivating proteins; ricin; ricin A-chain; momordin; Cibacron blue; difference spectra

    • Abstract


      The interaction of Cibacron blue F3GA with ribosome inactivating proteins, ricin, ricin A-chain and momordin has been investigated using difference absorption spectroscopy. Ricin was found to bind the dye with a 20- and 2-fold lower affinity than ricin A-chain and momordin, respectively. A time dependent increase in the amplitude of Cibacron blue difference spectrum in the presence of ricin was observed on addition of β-mercaptoethanol. Analysis of the kinetic profile of this increase showed a biphasic phenomenon and the observed rates were found to be independent of the concentration of β-mercaptoethanol. Kinetics of reduction of the intersubunit disulphide bond in ricin by β-mercaptoethanol showed that reductionper se is a second order reaction. Therefore, the observed changes in the difference spectra of Cibacron blue probably indicate a slow change in the conformation of ricin, triggered by reduction of the intersubunit disulphide bond.

    • Author Affiliations


      Shalini Sharma1 Sunil K Podder1

      1. Department of Biochemistry, Indian Institute of Science, Bangalore - 560 012, India
    • Dates

  • Journal of Biosciences | News

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      Posted on July 25, 2019

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