One-step purification of histone deacetylase from Escherichia coli cell-lysate by counter-current chromatography using aqueous two-phase system

Countercurrent chromatography as a frontier tool to discover new mechanical roles in liquid-liquid phase separation of cellular biomolecules

The development of countercurrent chromatography (CCC) technology enabled us to achieve higher peak resolutions and more shortened separation times even for protein separation using aqueous two-phase solvent systems composed of polyethylene glycol and inorganic salts (or dextrans). By eliminating the solid support matrix, all analytes can be recovered from the coiled column after the separation is completed. Recently, it has been found that droplets of biomolecules formed by liquid-liquid phase separation in cells closely relate to the transcription, regulation of signal transduction, and formation of amyloids. Meanwhile, although CCC is a separation technique based on liquid-liquid partitioning of analytes between two immiscible phases, the mechanism of separation could suggest some idea concerning the formation of biomolecule droplets in cells. This article describes the recent advances in the CCC apparatus, the coiled separation column, the choice of a suitable two-phase solvent system, and the application to separation and purification of bioactive macromolecules such as proteins and enzymes, and also discusses the possibility of CCC as a tool to reveal new mechanical roles of biomolecule droplets in the cellular environments.

Purification of active myrosinase from plants by aqueous two-phase counter-current chromatography

INTRODUCTION

Myrosinase (thioglucoside glucohydrolase; E.C. 3.2.1.147), is a plant enzyme of increasing interest and importance to the biomedical community. Myrosinase catalyses the formation of isothiocyanates such as sulforaphane (from broccoli) and 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate (from moringa), which are potent inducers of the cytoprotective phase-2 response in humans, by hydrolysis of their abundant glucosinolate (β-thioglucoside N-hydroxysulphate) precursors.

OBJECTIVE

To develop an aqueous two-phase counter-current chromatography (CCC) system for the rapid, three-step purification of catalytically active myrosinase.

METHODS

A high-concentration potassium phosphate and polyethylene glycol biphasic aqueous two-phase system (ATPS) is used with a newly developed CCC configuration that utilises spiral-wound, flat-twisted tubing (with an ovoid cross-section).

RESULTS

Making the initial crude plant extract directly in the ATPS and injecting only the lower phase permitted highly selective partitioning of the myrosinase complex before a short chromatography on a spiral disk CCC. Optimum phase retention and separation of myrosinase from other plant proteins afforded a 60-fold purification.

CONCLUSION

Catalytically active myrosinase is purified from 3-day broccoli sprouts, 7-day daikon sprouts, mustard seeds and the leaves of field-grown moringa trees, in a CCC system that is predictably scalable.

Advances in countercurrent chromatography for protein separations

Countercurrent chromatography (CCC) is a preparative purification technique working with biphasic liquid systems. One phase of the liquid system is selected to be the mobile phase, the other phase is the stationary phase, held still by centrifugal fields. Aqueous two-phase systems (ATPS) have demonstrated their use in biological purifications. This article reviews protein separations done by CCC using ATPS. The two types of CCC ‘columns’ – hydrostatic and hydrodynamic instruments – are presented. All commercially available CCC equipments are listed. The hydrostatic CCC columns have an interesting potential to purify proteins working with ATPS aqueous liquid phases. The ATPS properties are briefly summarized, giving the polyethylene glycol 1000/dipotassium phosphate/water ternary mass phase diagram, along with the full chemical compositions of the two aqueous phases of important mixtures of this ATPS. Most published protein purifications were performed in academic laboratories. The highest throughput listed is 1.65 g/h of pure lyzozyme, obtained using a 5.5 l hydrostatic CCC column.

Purification of Proteins From Cell-Culture Medium or Cell-Lysate by High-Speed Counter-Current Chromatography Using Cross-Axis Coil Planet Centrifuge

This review describes protein purifications from cell culture medium or cell-lysate by high speed counter-current chromatography using the cross-axis coil planet centrifuge. Purifications were performed using aqueous two phase systems composed of polyethylene glycols and dextrans.