Ligand binding interactions, human serum

Derrick studied the interaction of L-tryptophan and ibuprofen with human serum albumin (HSA),74 which is an abundant transport blood protein capable of binding efficiently several species.75 They acquired 1H NMR spectra of L-Tryptophan-HSA system for different ligand protein molar ratios, that is 3 1, 5 1, 7 1 and 10 1. The aromatic resonances of L-Tryptophan are difficult to be observed due to the overlap with HSA signals, even at 10 1 molar ratio, so that the spectral subtraction was performed. D values of L-Tryptophan were calculated by integration of the subtracted spectra and were in good agreement with those predicted by computer simulations. In the case of ibuprofen, only for 140 1 molar ratio, the resonances of ibuprofen are clearly visible also in this case, the... 

Ligand-induced conformational changes in the protein can result in both cooperative and antagonistic binding effects on other ligands binding to the same protein. An example of a cooperative interaction is the enhancement of the interactions of progesterone and testosterone with human serum albumin (HSA) by the palmitate ion. 

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