Influence of carbonate on the complexation of Cm(iii) with human serum transferrin studied by time-resolved laser fluorescence spectroscopy (TRLFS). (15th December 2014)

• Record Type: Journal Article
• Authors: Bauer, Nicole; Panak, Petra J.
• Is Part Of: New journal of chemistry. Volume 39:Number 2(2015:Feb.)
• Page Start: 1375
• Page End: 1381
• Publication Date: 2014-12-15
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c4nj01877j
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : The influence of carbonate on the complexation of Cm(iii ) with transferrin is investigated using TRLFS. The results prove directly that carbonate acts as a synergistic anion for Cm(iii ) complexation with transferrin. Abstract : The complexation of Cm(iii ) with transferrin is investigated in the pH range from 3.5 to 11.0 in the absence of carbonate and at c (carbonate)tot = 25 mM. In the absence of carbonate two Cm(iii ) transferrin species I and II are formed depending on pH. An increase of the total carbonate concentration favors the formation of the Cm(iii ) transferrin species II with Cm(iii ) bound at the Fe(iii ) binding site of transferrin at significantly lower pH values. The spectroscopic results directly prove that carbonate acts as a synergistic anion for Cm(iii ) complexation at the binding site of transferrin. At c (carbonate)tot = 25 mM the formation of the nonspecific Cm(iii ) transferrin species I is suppressed completely. Instead, three Cm(iii ) carbonate species Cm(CO3 ) +, Cm(CO3 )2 − and Cm(CO3 )3 3− are formed successively with increasing pH. The formation of Cm(iii ) carbonate species results in a decreased fraction of the Cm(iii ) transferrin species II at pH ≥ 7.4 which indicates that carbonate complexation is an important competition reaction for Cm(iii ) transferrin complexation at physiological carbonate concentration.