Eiteman M A, Hassinen C, Veide A
Department of Biological and Agricultural Engineering, University of Georgia, Athens 30602.
Biotechnol Prog. 1994 Sep-Oct;10(5):513-9. doi: 10.1021/bp00029a009.
A mathematical procedure was developed to predict the partition coefficients of the peptides AIIP, AWWP, AIIPAIIP and AWWPAWWP in poly(ethylene glycol) (PEG)/phosphate aqueous two-phase systems from amino acid hydrophobicities. In general, peptides containing tryptophan partition more into the PEG-enriched upper phase than analogous peptides containing isoleucine. Specifically, as the PEG concentration difference between the phases increased in a PEG/potassium phosphate aqueous two-phase system, the peptide AIIP was observed to have a partition coefficient ranging from 1.2 to 1.6, AIIPAIIP from 2.4 to 5.7, AWWP from 13.5 to 32.2, and AWWPAWWP from 43 to 170. The model was extended to predict the partitioning of a staphylococcal protein A derivative (ZZ) modified with these four peptides. As predicted, the protein modified with isoleucine-containing peptides had lower partition coefficients than the protein modified with tryptophan-containing peptides. The partition coefficient of the ZZ protein ranged from 0.35 to 0.20, that of ZZAIIPAIIP from 0.58 to 0.48, and that of ZZAWWPAWWP from 3.5 to 5.3 in these systems. The results show that short peptide handles can significantly enhance the partitioning of proteins in aqueous two-phase systems. The relationship between the model and the surface exposure of peptide handles and the utility of the model to aid in the design of such handles to enhance purifications are also discussed.
已开发出一种数学方法，可根据氨基酸疏水性预测肽AIIP、AWWP、AIIPAIIP和AWWPAWWP在聚乙二醇（PEG）/磷酸盐双水相体系中的分配系数。一般来说，含色氨酸的肽比含异亮氨酸的类似肽更多地分配到富含PEG的上相中。具体而言，在PEG/磷酸钾双水相体系中，随着两相之间PEG浓度差的增加，观察到肽AIIP的分配系数在1.2至1.6之间，AIIPAIIP在2.4至5.7之间，AWWP在13.5至32.2之间，AWWPAWWP在43至170之间。该模型被扩展以预测用这四种肽修饰的葡萄球菌蛋白A衍生物（ZZ）的分配情况。如所预测的，用含异亮氨酸肽修饰的蛋白质的分配系数低于用含色氨酸肽修饰的蛋白质。在这些体系中，ZZ蛋白的分配系数在0.35至0.20之间，ZZAIIPAIIP在0.58至0.48之间，ZZAWWPAWWP在3.5至5.3之间。结果表明，短肽柄可显著增强蛋白质在双水相体系中的分配。还讨论了该模型与肽柄的表面暴露之间的关系以及该模型在辅助设计此类柄以增强纯化方面的实用性。
