Synthesis of biotinylated cyclosporin A and studies on its interaction with human cyclophilin A

Biotinylated cyclosporin A was synthesized by condensing the amino - deriva tive of cyclosporin A with ethyl N - ( N - biotinyl - epsilon - aminocapron yl) - epsilon - aminocaproate, which was preformed from coupling biotin and the ethyl ester of dimeric epsilon - aminocaproic acid to extend the carbo xyl group of biotin for 14 atoms. Both of drug western blot and surface pla smon resonance (SPR) proved that the biotinylated cyclosporin A remained th e capacity of binding human cyclophilin A.