Prashant N. Bhatt

Pr（III） and Nd（III） Absorption Spectroscopic Probe to Investigate Interaction with Lysozyme （HEW）

Abstract Pr(III) and Nd(III) can be utilized as absorption spectroscopic probes to investigate the interaction of biomolecules like Lysozyme (HEW) with Ca (II) in-vitro; the most abundant metal ion in the human body system. The spectroscopic techniques involving comparative absorption, absorption difference, and quantitative intensity analysis using 4f-4f transitions are utilized for changes in the inner sphere coordination pattern of Pr(III) and Nd(III) in solution as well as in solid state. The present study deals with an important biomolecule in human metabolism, that is, Lysozyme (HEW). The absorption spectral parameters such as the oscillator strength (P), the Judd-Ofelt (Tλ) intensity parameters, and the Slater-Condon inter electronic parameters are calculated using chi square methods. The obtained results are used to determine the probable geometry of the complex in the solution, the nature of the bond between Pr(III)/Nd(III) with lysozyme, and the inner sphere coordination environment of f-f transitions. The results obtained from various experimental conditions are utilized to investigate the coordination changes in the Pr(III)/Nd(III) complexes caused by different coordinating sites of lysozyme, normalized bite, denticity, the solvent nature, the coordination number, the nature of bond and other parameters to mimic the interaction of the Ca(II) ion with such biomolecule.

Eu（III） Indirect Probe to Investigate Interaction of DOPA （3, 4, Di-Hydroxyphenylalanine） and Dopamine （3, 4-Dihydroxy Phenyl Ethyl Amine） Using Electrochemical Methods

Abstract Eu (III) can be utilized as an indirect electrochemical probe to investigate the interaction of bio-molecules such as DOPA and Dopamine with Ca (II) in vitro. The interaction of DOPA and Dopamine with Eu(III)-Eu(II) redox pair was investigated by electrochemical techniques. Both the neurotransmitters are structurally related and undergo interaction with Eu (III). Eu (III) coordinates with DOPA and Dopamine through five-member chelate rings via carboxylic oxygen and amino nitrogen. The electrode kinetic parameters viz, transfer coefficient (αna), diffusion coefficient (D), forward heterogeneous rate constant (kofh) were evaluated for Eu(III)-DOPA/Eu(III)-Dopamine. The results obtained were used to investigate the nature of interaction of Eu (III) with multi-donor biomolecules. The possible mechanism was also proposed.

An absorption spectral study of Nd (III) with glutathione (reduced), GSH in aqueous and aquated organic solvent in presence and absence of Zn (II)

Abstract The coordination chemistry of glutathione (reduced) GSH is of great importance as it acts as an excellent model system for the binding of metal ions. The GSH complexation with metal ions is involved in the toxicology of different metal ions. Its coordination behaviour for soft metal ions and hard metal ions is found different because of the structure of GSH and its different potential binding sites. We have studied two chemically dissimilar metal ions viz. Nd (III) being hard metal ion, which will prefer hard donor sites like carboxylic groups, and Zn (II) the soft metal ion more suited to peptide—NH and sulfhydryl groups. The absorption difference and comparative absorption spectroscopy involving 4 f –4 f transitions of the heterobimetallic complexation of GSH with Nd (III) and Zn (II) has been explored in aqueous and aquated organic solvents. The changes in the oscillator strengths of different 4 f –4 f bands and Judd–Ofelt intensity ( T λ ) parameters determined experimentally is being used to investigate the complexation of GSH. The in vivo intracellular complexation of GSH with Ca (II) in presence of Zn (II) ion has been mimicked through Nd (III)–GSH–Zn (II) absorption spectral studies in vitro.