Enhanced Extraction of Amino Compounds Using Dicyclohexyl-18-crown-6 as a Ligand in an Aqueous Two-phase System

Abstract

Various studies on the complexation between crown ethers and biomolecules bearing primary amino groups have been conducted. In the present study, extraction of amino compounds based on the complexation with a crown ether in Li 2 SO 4 /PEG aqueous two-phase system has been examined. In the series of crown ethers and their analogues, only dicyclohexano-18-crown-6 (DCH18C6) functioned as a ligand for enhancing the extraction of amino compounds into the PEG-rich phase. The number of primary amino groups of the guest molecules as well as their hydrophobicity is dominant for enhancing the extraction based on the complexation with DCH18C6. From the results of slope analysis, the number of DCH18C6 molecules complexing with an amino compound agreed with the number of primary amino groups.

Recognition of exterior protein surfaces using artificial ligands based on calixarenes, crown ethers, and tetraphenylporphyrins

“…The crown ether DCH18C6 is effective for controlling the distribution of cytochrome c in Li 2 SO 4 /PEG ATPS [104,105]. The lysine-rich protein cytochrome c is distributed in a hydrophobic PEG-rich phase by multiple interactions between DCH18C6 molecules and the lysine residues.…”

Intensified solvent extraction of L-tryptophan in small channels using D2EHPA

“…These features make amino acids hydrophilic at all values of pH and therefore difficult to remove from aqueous solutions in conventional solvent extraction. To enhance the extractive potential of organic solvents, certain extractants, such as crown ether based extractant (18-crown-6, benzo-18-crown-6, dibenzo-18-crown-6, dicyclohexyl-18-crown-6) [15][16][17][18][19][20], cationic extractants Di(2ethylhexyl)phosphoric acid (D2EHPA) [11,[21][22][23][24][25][26] and metal complexes (such as BINAP-metal, MeO-BIPHEP-metal, and SDP-metal) [27][28][29][30][31], are added in the organic phase. Crown ether based extractants and D2EHPA form stable hydrophobic complexes with the amino acids via hydrogen bonding and have long been used in their liquid-liquid extraction.…”

Evaluation of the Hydrophilic and Hydrophobic Balance for the Complex between Indomethacin and Casein Hydrolysate Using an Aqueous Two-Phase System

“…The surface net hydrophobicity of protein (HFS) is directly related to the distribution ratio [14]. ATPSs can be used to estimate the hydrophobicity of the complex between small organic molecules and biomolecules [17,18]. Therefore, the hydrophobicity of Indo-Pep was also evaluated using the poly(ethylene glycol)/dextran (PEG/DEX) ATPS.…”