Cyclodextrins are widely used for various purposes and limited because of it′s low solubility.Branched cyclodextrins have attracted more and more attention because of their many advantages such as higher solubility i...Cyclodextrins are widely used for various purposes and limited because of it′s low solubility.Branched cyclodextrins have attracted more and more attention because of their many advantages such as higher solubility in water.In this study a new method for synthesizing maltosyl(α-1→6)β-cyclodextrin with a high yield was described.Mal-β-CD was synthesized through the reverse reaction of Bacillus licheniformis pullulanase and identified.The factors which affect the formation of maltosyl(α1→6)β-cyclodextrin were studied and the optimum conditions were obtained as follows: 250 U/g β-CD of enzyme amount,molar ratio of maltose to β-CD 12∶1～16∶1,a substrate mass fraction of 80%,the pH of reaction mixture 4.5,reaction temperature 70 ℃ and reaction time 60 h respectively.The product was separated by Sephadex G25 column and further purified by Bio-gel P-2 column.Maltosyl(α-1→6)β-cyclodextrin was identified by IR,ESI-MS and NMR.It was proved to be a effective method to synthesize maltosyl(α-1→6)β-cyclodextrin by using Bacillus licheniformis pullulanase.The yield of Mal-β-CD was about 56% under the optimal conditions.展开更多
The interactions between several peptides with low molecular weight (guest, NH2 Arg Arg Trp Trp H 2; NH2 Arg Trp Arg Trp H 3; NH2 Trp Arg Arg Trp H 4; NH2 Arg Arg Trp Trp Trp Trp H 5; NH2 Trp Trp Arg Arg Trp Trp H 6; ...The interactions between several peptides with low molecular weight (guest, NH2 Arg Arg Trp Trp H 2; NH2 Arg Trp Arg Trp H 3; NH2 Trp Arg Arg Trp H 4; NH2 Arg Arg Trp Trp Trp Trp H 5; NH2 Trp Trp Arg Arg Trp Trp H 6; NH2 Arg Arg Trp Trp Trp Trp Trp Trp H 7; NH2 Arg Arg Trp Trp Trp Trp Trp Trp Trp Trp H 8) and β cyclodextrin dimer (host, 1) bridged with the derivative of (1R, 3R) 1 aminocyclobutane cis 1,3 dicar boxylic acid were investigated by using fluorescence polarization method in buffer aqueous solution (pH 7.4) at 298K. The binding constants of the cyclodextrin dimer 1 to the guests 2 8 were determined. It was shown that there was a cooperative action of the two cavities of a cyclodextrin dimer in the binding of large substrates, and that the structure and properties of amino acid in the peptides played very important roles in the synergic complexation between host and guest.展开更多
文摘Cyclodextrins are widely used for various purposes and limited because of it′s low solubility.Branched cyclodextrins have attracted more and more attention because of their many advantages such as higher solubility in water.In this study a new method for synthesizing maltosyl(α-1→6)β-cyclodextrin with a high yield was described.Mal-β-CD was synthesized through the reverse reaction of Bacillus licheniformis pullulanase and identified.The factors which affect the formation of maltosyl(α1→6)β-cyclodextrin were studied and the optimum conditions were obtained as follows: 250 U/g β-CD of enzyme amount,molar ratio of maltose to β-CD 12∶1～16∶1,a substrate mass fraction of 80%,the pH of reaction mixture 4.5,reaction temperature 70 ℃ and reaction time 60 h respectively.The product was separated by Sephadex G25 column and further purified by Bio-gel P-2 column.Maltosyl(α-1→6)β-cyclodextrin was identified by IR,ESI-MS and NMR.It was proved to be a effective method to synthesize maltosyl(α-1→6)β-cyclodextrin by using Bacillus licheniformis pullulanase.The yield of Mal-β-CD was about 56% under the optimal conditions.
文摘The interactions between several peptides with low molecular weight (guest, NH2 Arg Arg Trp Trp H 2; NH2 Arg Trp Arg Trp H 3; NH2 Trp Arg Arg Trp H 4; NH2 Arg Arg Trp Trp Trp Trp H 5; NH2 Trp Trp Arg Arg Trp Trp H 6; NH2 Arg Arg Trp Trp Trp Trp Trp Trp H 7; NH2 Arg Arg Trp Trp Trp Trp Trp Trp Trp Trp H 8) and β cyclodextrin dimer (host, 1) bridged with the derivative of (1R, 3R) 1 aminocyclobutane cis 1,3 dicar boxylic acid were investigated by using fluorescence polarization method in buffer aqueous solution (pH 7.4) at 298K. The binding constants of the cyclodextrin dimer 1 to the guests 2 8 were determined. It was shown that there was a cooperative action of the two cavities of a cyclodextrin dimer in the binding of large substrates, and that the structure and properties of amino acid in the peptides played very important roles in the synergic complexation between host and guest.
