Eiteman M A, Gainer J L
Department of Chemical Engineering, University of Virginia, Charlottesville 22903-2442.
Biochim Biophys Acta. 1991 Apr 9;1073(3):451-5. doi: 10.1016/0304-4165(91)90214-2.
A series of isomeric dipeptides, i.e., those containing identical residues but in different order such as Trp-Gly versus Gly-Trp, was partitioned in a poly(ethylene glycol) (PEG)/magnesium sulfate (MgSO4) aqueous two-phase system. Dipeptides having a more hydrophobic character favored the upper (PEG) phase. Moreover, the partition coefficients for isomeric dipeptides are different, with the partition coefficients for dipeptides containing the more hydrophobic residue in the C-terminal position being, in general, greater than the partition coefficients for corresponding isomers which contain the more hydrophobic residue in the N-terminal position. These observations can be attributed to the different interactions that the isomers have with specific two-phase systems.
一系列同分异构二肽，即那些含有相同残基但顺序不同的二肽，如色氨酸 - 甘氨酸（Trp - Gly）与甘氨酸 - 色氨酸（Gly - Trp），在聚乙二醇（PEG）/硫酸镁（MgSO4）水两相体系中进行分配。具有更强疏水性的二肽更倾向于上层（PEG）相。此外，同分异构二肽的分配系数不同，一般来说，C 端含有疏水性更强残基的二肽的分配系数大于相应的 N 端含有疏水性更强残基的同分异构体的分配系数。这些观察结果可归因于异构体与特定两相体系之间不同的相互作用。
