Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples

Singh, Inderjit; Mishra, Lokpati; Yadav, J. R.; Nadar, M. Y.; Rao, D. D. Bhaktavatsala; Pradeepkumar, K.S.

doi:10.1016/j.apradiso.2015.06.012

Cited by 4 publications

(1 citation statement)

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“…Although there are stringent safety measures during these processes, there always remains a risk that these radionuclides can enter the human body through any of the routes, namely inhalation, ingestion, and injection. Upon entry into the body they are transported to various tissues, cells via blood mainly through the iron carrier serum transferrin (sTf) protein 1,2,4‐12 . Most of the An isotopes especially, 228 Th, 238 Pu, 239 Pu, 241 Am, 242 Cm, 244 Cm, and 237 Np are mainly α emitters and are highly radiotoxic 3 .…”

Section: Introductionmentioning

confidence: 99%

MD simulation reveals differential binding of Cm(III) and Th(IV) with serum transferrin at acidic pH

2020

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The iron carrier human serum transferrin (sTf) is known to transport other metals, including some actinides (An). Radiotoxic An are routinely involved in the nuclear fuel cycle and the possibility of their accidental exposure cannot be ruled out. Understanding An interaction with sTf assumes a greater significance for the development of safe and efficacious chelators for their removal from the blood stream. Here we report several 100 ns equilibrium MD simulations of Cm(III)‐ and Th(IV)‐loaded sTf at various protonation states of the protein to explore the possibility of the two An ions release and speciation. The results demonstrate variation in protonation state of dilysine pair (K206 and K296) and the tyrosine (Y188) residue is necessary for the opening of Cm(III)‐bound protein and the release of the ion. For the tetravalent thorium, protonation of dilysine pair suffices to cause conformational changes of protein. However, in none of the protonation states, Th(IV) releases from sTf because of its strong electrostatic interaction with D63 in the first shell of the sTf binding cleft. Analysis of hydrogen bond, water bridge, and the evaluation of potential of mean forces of the An ions' release from sTf, substantiate the differential behavior of Cm(III) and Th(IV) at endosomal pH. The results provide insight in the regulation of Cm(III) and Th(IV) bioavailability that may prove useful for effective design of their decorporating agents and as well may help the future design of radiotherapy based on tetravalent ions.

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