Novel dendritic displacers

Phe-D and Leu-D

with L-lysine as the dendritic branch and phenylalanine or leucine as the branching agent were synthesized by the solid-phase peptide coupling method on 1% cross-linked polystyrene bead functionalized with Fmoc-phenylalanine.The parameters in the steric-mass action (SMA) model for the novel displacers and their displacement performance were determined by chromatographic experiments

adsorption equilibrium and batch displacement experiments

and were compared with a typical displacer

N-α-benzoyl-L-arginine ethyl ester (BAEE）.Based on the SMA model parameters

affinity ranking plots of the displacers and proteins were obtained.The results showed that the dynamic affinities of the displacers reduced with an increase of the logarithm of the partition ratio of the displacer (lgΔ）.At a lgΔ less than 0.845

BAEE exhibited the highest dynamic affinity.At lgΔ from 0.845 to 3.08

Phe-D had the strongest dynamic affinity to the stationary phase.The batch displacement data for cytochrome C and α-chymotrypsinogen A demonstrated that the novel displacers gave a higher percentage of protein displacement from SP Sepharose HP due to more primary amine groups in the displacer molecules.On the other hand

the percentage of protein displacement increased by 70% due to the introduction of a phenyl group

confirming the enhancement effect of aromatic groups on protein displacement.