Comparison of the binding behavior of several histidine-containing proteins with immobilized copper(II) complexes of 1,4,7-triazacyclononane and 1,4-bis(1,4,7-triazacyclononan-1-yl)butane

摘要: Abstract The protein binding characteristics of the immobilized binucleating chelate system, 1,4-bis(1,4,7-triazacyclononan-1-yl)butane (tacn2butane), complexed with Cu2+ ions have been investigated hen egg white lysozyme, horse skeletal muscle myoglobin and heart cytochrome C, as well three histidine-rich proteins, serum albumin, transferrin, α2-macroglobulin, present in partially fractionated human serum. effects pH, ionic strength elution buffers on examined compared those analogous mononuclear copper complex 1,4,7-triazacyclononane (tacn). Cu2+-tacn2butane system was generally found to exhibit higher affinities than Cu2+-tacn suggesting that presence binuclear copper(II) species leads enhanced coordinative interaction surface-exposed amino acid residues studied proteins. However, under some buffer conditions dependencies pH these metal ion affinity chromatographic (IMAC) systems were consistent electrostatic, hydrophobic π-bonding interactions playing a significant secondary role addition dominant interactions. As such, results indicated selectivities not solely dependent histidine content protein. In accord this conclusion, differences adsorbents for α2-macroglobulin observed depending choice buffer. This attribute suggests additional selectivity features can be realised separation specific proteins new class adsorbent.