PARTITION EFFICIENCY OF NEWLY DESIGNED LOCULAR MULTILAYER COIL FOR COUNTERCURRENT CHROMATOGRAPHIC SEPARATION OF PROTEINS USING SMALL-SCALE CROSS-AXIS COIL PLANET CENTRIFUGE WITH AQUEOUS-AQUEOUS POLYMER PHASE SYSTEMS

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.

Improved Separations of Proteins and Sugar Derivatives Using the Small-Scale Cross-Axis Coil Planet Centrifuge with Locular Multilayer Coiled Columns

1 BACKGROUND

Countercurrent chromatography (CCC) is liquid-liquid partition chromatography without using a solid support matrix. This technique requires further improvement of partition efficiency and shortening theseparation time.

2 METHODS

The locular multilayer coils modified with and without mixer glass beads were developed for the separation of proteins and 4-methylumbelliferyl (MU) sugar derivatives using the small-scale cross-axis coil planet centrifuge.

3 RESULTS

Proteins were well separated from each other and the separation was improved at a low flow rate of the mobile phase. On the other hand, 4-MU sugar derivatives were sufficiently resolved with short separation time at a highflow rate of the mobile phase under satisfactory stationary phase retention.

4 CONCLUSION

Effective separations were achieved using the locular multilayer coil for proteins with aqueous-aqueous polymer phase systems and for 4-MU sugar derivatives with organic-aqueous two-phase solvent systems by inserting a glass bead into each locule.

Partition Efficiency of High-Pitch Locular Multilayer Coil for Countercurrent Chromatographic Separation of Proteins Using Small-Scale Cross-Axis Coil Planet Centrifuge and Application to Purification of Various Collagenases with Aqueous-Aqueous Polymer Phase Systems

Partition efficiency of the high-pitch locular multilayer coil was evaluated in countercurrent chromatographic (CCC) separation of proteins with an aqueous-aqueous polymer phase system using the small-scale cross-axis coil planet centrifuge (X-axis CPC) fabricated in our laboratory. The separation column was specially made by high-pitch (ca 5 cm) winding of 1.0 mm I.D., 2.0 mm O.D. locular tubing compressed at 2 cm intervals with a total capacity of 29.5 mL. The protein separation was performed using a set of stable proteins including cytochrome C, myoglobin, and lysozyme with the 12.5% (w/w) polyethylene glycol (PEG) 1000 and 12.5% (w/w) dibasic potassium phosphate system (pH 9.2) under 1000 rpm of column revolution. This high-pitch locular tubing yielded substantially increased stationary phase retention than the normal locular tubing for both lower and upper mobile phases. In order to demonstrate the capability of the high-pitch locular tubing, the purification of collagenase from the crude commercial sample was carried out using an aqueous-aqueous polymer phase system. Using the 16.0% (w/w) PEG 1000 - 6.3% (w/w) dibasic potassium phosphate - 6.3% (w/w) monobasic potassium phosphate system (pH 6.6), collagenase I, II, V and X derived from Clostridium hystolyticum were separated from other proteins and colored small molecular weight compounds present in the crude commercial sample, while collagenase N-2 and S-1 from Streptomyces parvulus subsp. citrinus were eluted with impurities at the solvent front with the upper phase. The collagenase from C. hystolyticum retained its enzymatic activity in the purified fractions. The overall results demonstrated that the high-pitch locular multilayer coil is effectively used for the CCC purification of bioactive compounds without loss of their enzymatic activities.