Chiral Separation Mechanisms in Protein-Based HPLC Columns. 2. Kinetic Studies of (R)- and (S)-Warfarin Binding to Immobilized Human Serum Albumin

1996 ◽  
Vol 68 (7) ◽  
pp. 1218-1225 ◽  
Author(s):  
Bounthon Loun ◽  
David S. Hage
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Chiral Separation ◽  
Kinetic Studies ◽  
Separation Mechanisms

Kinetic Studies of Copper(II)-exchange from L-Histidine to Human Serum Albumin and Diglycyl-L-histidine, a Peptide Mimicking the Copper(II)-transport Site of Albumin

1975 ◽  
Vol 53 (5) ◽  
pp. 710-715 ◽  
Author(s):  
Show-Jy Lau ◽  
Bibudhendra Sarkar
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Exchange Rates ◽  
Human Serum ◽  
Kinetic Studies ◽  
Side Chain ◽  
Exchange Reactions ◽  
Equilibrium Study ◽  
Rate Determining Step ◽  
The Difference

The Cu(II)-exchange reactions of L-histidine with human serum albumin and diglycyl-L-histidine were studied at pH 7.53 in 0.1 MN-ethylmorpholine–HCl buffer. The exchange rates from L-histidine to albumin and peptide were determined as 0.67 and 0.42 s−1 respectively. Those from albumin and peptide to L-histidine were obtained as 0.04 and 0.07 s−1 respectively. This result is in accord with the earlier observations of the equilibrium study that the peptide has about half the Cu(II)-binding affinity as compared to albumin. The difference in the Cu(II)-exchange rates of albumin and peptide may reflect the influence of either the COOH-terminal free carboxyl group of the peptide or the side-chain residues of the Cu(II)-binding site in the native protein or both. An exchange mechanism is proposed in which the ternary complexes are shown to play the important role in the rate-determining step in the Cu(II)-exchange between a macromolecule and a small substance.

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