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Effects of N ‐Acetyl‐L‐Cysteine‐Capped CdTe Quantum Dots on Bovine Serum Albumin and Bovine Hemoglobin: Isothermal Titration Calorimetry and Spectroscopic Investigations
Author(s) -
Sun Haoyu,
Cui Erqian,
Tan Zhigang,
Liu Rutao
Publication year - 2014
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/jbt.21597
Subject(s) - bovine serum albumin , isothermal titration calorimetry , chemistry , fluorescence , circular dichroism , titration , quantum dot , quenching (fluorescence) , analytical chemistry (journal) , crystallography , photochemistry , chromatography , inorganic chemistry , materials science , nanotechnology , physics , quantum mechanics
ABSTRACT The interactions of N ‐acetyl‐L‐cysteine‐capped CdTe quantum dots (QDs) with bovine serum albumin (BSA) and bovine hemoglobin (BHb) were investigated by isothermal titration calorimetry (ITC), fluorescence, synchronous fluorescence, fluorescence lifetime, ultraviolet–visible absorption, and circular dichroism techniques. Fluorescence data of BSA–QDs and BHb–QDs revealed that the quenching was static in every system. While CdTe QDs changed the microenvironment of tryptophan in BHb, the microenvironment of BSA kept unchanged. Adding CdTe QDs affected the skeleton and secondary structure of the protein (BSA and BHb). The ITC results indicated that the interaction between the protein (BSA and BHb) and QDs‐612 was spontaneous and the predominant force was hydrophobic interaction. In addition, the binding constants were determined to be 1.19 × 10 5 L mol −1 (BSA–QDs) and 2.19 × 10 5 L mol −1 (BHb–QDs) at 298 K. From these results, we conclude that CdTe QDs have a larger impact on the structure of BHb than BSA.