Three-phase affinity partitioning of proteins

Purification and characterization of a new trypsin-like protease from Crotalaria stipularia

Proteases are the main enzymes traded worldwide-comprising 60% of the total enzyme market-and are fundamental to the degradation and processing of proteins and peptides. Due to their high commercial demand and biological importance, there is a search for alternative sources of these enzymes. Crotalaria stipularia is highlighted for its agroecological applications, including organic fertilizers, nematode combat, and revegetation of areas contaminated with toxic substances. Considering the pronounced biotechnological functionality of the studied species and the necessity to discover alternative sources of proteases, we investigated the extraction, purification, and characterization of a protease from seeds of the C. stipularia plant. Protease isolation was achieved by three-phase partitioning and single-step molecular exclusion chromatography in Sephacryl S-100, with a final recovery of 47% of tryptic activity. The molecular mass of the isolated enzyme was 40 kDa, demonstrating optimal activities at pH 8.0 and 50 °C. Enzymatic characterization demonstrated that the protease can hydrolyze the specific trypsin substrate, BApNA. This trypsin-like protease had a Km, Vmax, Kcat, and catalytic efficiency constant of 0.01775 mg/mL, 0.1082 mM/min, 3.86 s-1, and 217.46, respectively.

Partitioning and recovery of proteases from lizardfish (Saurida micropectoralis) stomach using combined phase partitioning systems and their storage stability

Partitioning and recovery of proteases from stomach extract (SE) and acidified stomach extract (ASE) of lizardfish using a three-phase partitioning (TPP) system in combination with an aqueous two-phase system (ATPS) was optimized. The highest yield and purity were obtained in the interphase of the TPP system, which consisted of a SE or ASE to t-butanol ratio of 1.0 : 0.5 in the presence of 40% (w/w) (NH₄)₂SO₄. Both TPP fractions were further subjected to ATPS. Phase compositions of ATPS including PEG molecular mass and concentrations as well as types and concentrations of salts influenced protein partitioning. The best ATPS conditions for protease partitioning into the top phase from TPP fractions of SE and ASE were 15% Na₃C₆H₅O₇-20% PEG1000 and 20% Na₃C₆H₅O₇-15% PEG1000, which increased the purity by 4-fold and 5-fold with the recovered activity of 82% and 77%, respectively. ATPS fractions of SE and ASE were subsequently mixed with several PEGs and salts for back extraction (BE). BE using 25% PEG8000-5% Na₃C₆H₅O₇ gave the highest PF and yield for both ATPS fractions. SDS-PAGE investigation revealed that the decrease in contaminating protein bands was observed after the combined partitioning systems. BE fractions of SE and ASE were quite stable at -20 and 0 °C up to 14 days. Therefore, the combination of TPP, ATPS and BE could be effectively applied to recover and purify proteases from the stomach of lizardfish.

Integrated Approach to Extract and Purify Proteins from Honey by Ionic Liquid-Based Three-Phase Partitioning

The purification of value-added compounds by three-phase partitioning (TPP) is a promising alternative to conventional processes since the target compound can be easily recovered from the liquid-liquid interphase. Although this technique has been successfully applied to the recovery of proteins, the minimization of the use of salts and solvents must be pursued to improve the overall process sustainability. Accordingly, we have here investigated the use of biobased glycine-betaine ionic liquids (IL) directly with honey, a carbohydrate-rich matrix, as phase-forming components of TPP systems. These ILTPP systems were applied in the purification of major royal jelly proteins (MRJPs) from honey. The results obtained show that MRJPs mostly precipitate in the ILTPP interphase, with a recovery yield ranging between 82.8% and 97.3%. In particular, MRJP1 can be obtained with a purity level up to 90.1%. Furthermore, these systems allow the simultaneous separation of antioxidants and carbohydrates to different liquid phases. The proposed approach allows the separation of proteins, antioxidants, and carbohydrates from honey in a single step, while using only ILs and a real carbohydrate-rich matrix, thus being sustainable TPP processes.

Three phase partitioning to concentrate milk clotting proteases from Wrightia tinctoria R. Br and its characterization

Wrightia tinctoria stem proteases were partially purified for the first time through a non-chromatographic technique, three phase partitioning (TPP), to concentrate the milk clotting proteases. Various parameters like salt and solvent concentration that affect the partitioning of the protease were examined. Maximum recovery and purification fold of the protease activity were found in the interfacial phase (IP) with 60% ammonium sulphate and 1:1 crude enzyme to t-butanol. Optimum pH and temperature of the enzyme fraction were found to be 7.5 and 50 °C respectively. Inhibition studies revealed its serine nature. Non-denaturing PAGE, Zymography and 2D PAGE of IP revealed presence of three different caseinolytic proteases of molecular weights 95.62 kDa, 91.11 kDa and 83.23 kDa with pI 3.89, 5.45 and 5.43 respectively. Both aqueous and lyophilized form of IP were remarkably stable retaining complete activity at 4 °C for 3 weeks. Electrophoretic analysis of casein hydrolysate by IP at different incubation time indicated a time dependent substrate subunit specificity with hydrolysis of κ-casein commencing after 10 min followed by α and β caseins. This pattern was found similar to that by commercial vegetable coagulant, Enzeco®. Study details the effectiveness of TPP concentrated W. tinctoria proteases as a vegetable coagulant alternative in cheese making.

Use of TPP and ATPS for partitioning and recovery of lipase from Pacific white shrimp (Litopenaeus vannamei) hepatopancreas

Lipase recovery from Pacific white shrimp hepatopancreas using a three-phase partitioning (TPP) system in combination with an aqueous two-phase system (ATPS) was studied. TPP system was formed with a simultaneous addition of salt directly to crude extract (CE) followed by an organic solvent addition. The various process parameters required for efficient purification of lipase were optimized. The best lipase yield (87.41%) and purification fold (PF) (3.49-fold) were obtained in the interphase of TPP system, which consisted of the CE to t-butanol ratio of 1:1 (v/v) in the presence of 50% (w/v) (NH4)2SO4. Subsequently, TPP fraction was subjected to ATPS. Effects of phase compositions including PEG molecular weight and concentration, types and concentration of salts, NaCl addition and system pH on lipase partitioning were investigated. With the application of 25% (w/w) PEG1000 and 15% (w/w) MgSO4, at pH 5.0 was found most appropriate since high lipase PF (5.19-fold) and yield (78.46%) in top phase were obtained. The partitioned enzyme exhibited optimal activity at pH 8.0 and 55 °C and was stable at a temperature range of 0-40 °C and a pH range of 7-10. The partitioned lipase showed high tolerance in the presence of ethanol and methanol. Hence, the combined partitioning systems, TPP-ATPS, were found to be an attractive technique for the recovery and partial purification of lipase from Pacific white shrimp hepatopancreas.

Simultaneous purification and refolding of proteins by affinity precipitation and macro (affinity ligand)-facilitated three phase partitioning (MLFTPP)

This chapter describes two simple interrelated non-chromatographic methods of protein purification. In the first method, called affinity precipitation, inherent affinity of reversibly soluble-insoluble polymers (also called stimuli-sensitive or smart polymers) is exploited to form an affinity complex in free solution with target protein. The affinity complex is precipitated by a suitable change in the medium. The desired protein is dissociated from the smart polymer. In the second method called macro (affinity ligand)-facilitated three phase partitioning (MLFTPP), the affinity complex is precipitated at an interface between upper t-butanol-rich phase and lower aqueous phase. These three phases are achieved by adding appropriate amounts of ammonium sulfate and t-butanol to the initial crude extract. In the first protocol, sequential MLFTPP is used with two different smart polymers to purify pectinase and cellulase from a single crude preparation. The second protocol illustrates the application of the affinity precipitation in simultaneous purification and refolding of a urea-denatured xylanase.

Three-phase partitioning as a rapid and easy method for the purification and recovery of catalase from sweet potato tubers (Solanum tuberosum)

Three-phase partitioning (TPP) was used to purify and recover catalase from potato crude extract. The method consists of ammonium sulfate saturation, t-butanol addition, and adjustment of pH, respectively. The best catalase recovery (262 %) and 14.1-fold purification were seen in the interfacial phase in the presence of 40 % (w/v) ammonium sulfate saturation with 1.0:1.0 crude extract/t-butanol ratio (v/v) at pH 7 in a single step. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the enzyme showed comparatively purification and protein molecular weight was nearly found to be 56 kDa. This study shows that TPP is a simple, economical, and quick method for the recovering of catalase and can be used for the purification process.

Applications of Alginate in Bioseparation of Proteins

Alginate is a polysaccharide that is a block polymer consisting of block units of guluronic acid and mannuronic acid. It shows inherent biological affinity for a variety of enzymes such as pectinase, lipase, phospholipase D, a and ss amylases and glucoamylase. Taking advantage of its precipitation with Ca2+ and the above-mentioned property, alginate has been used for purification of these enzymes by affinity precipitation, aqueous two phase separation, macroaffinity ligand facilitated three phase partitioning, immobilized metal affinity chromatography and expanded bed affinity chromatography. Thus, this versatile marine resource has tremendous potential in bioseparation of proteins.

New Functions of the Thylakoid Membrane Proteome of Arabidopsis thaliana Revealed by a Simple, Fast, and Versatile Fractionation Strategy

Identification of membrane proteomes remains challenging. Here, we present a simple, fast, and scalable off-line procedure based on three-phase partitioning with butanol to fractionate membrane proteomes in combination with both in-gel and in-solution digestions and mass spectrometry. This should help to further accelerate the field of membrane proteomics. Using this new strategy, we analyzed the salt-stripped thylakoid membrane of chloroplasts of Arabidopsis thaliana. 242 proteins were identified, at least 40% of which are integral membrane proteins. The functions of 86 proteins are unknown; these include proteins with TPR, PPR, rhodanese, and DnaJ domains. These proteins were combined with all known thylakoid proteins and chloroplast (associated) envelope proteins, collected from primary literature, resulting in 714 non-redundant proteins. They were assigned to functional categories using a classification developed for MapMan (Thimm, O., Blasing, O., Gibon, Y., Nagel, A., Meyer, S., Kruger, P., Selbig, J., Muller, L. A., Rhee, S. Y., and Stitt, M. (2004) Plant J. 37, 914-939), updated with information from primary literature. The analysis elucidated the likely location of many membrane proteins, including 190 proteins of unknown function, holding the key to better understanding the two membrane systems. The three-phase partitioning procedure added a new level of dynamic resolution to the known thylakoid proteome. An automated strategy was developed to track possible ambiguous identifications to more than one gene model or family member. Mass spectrometry search results, ambiguities, and functional classifications can be searched via the Plastid Proteome Database.

Alternative bioseparation operations: life beyond packed-bed chromatography

Chromatography is undoubtedly the workhorse of downstream processes, affording high resolution for bioseparations. At the same time, it has the notoriety of being the single largest cost center in downstream processing and of being a low-throughput operation. Consequently, 'chromatography alternatives' are an attractive proposition, even if only a reduction in the extent of use of packed beds can be realized. This paper reviews the current state of unit operations posing as chromatography alternatives--including membrane filtration, aqueous two-phase extraction, three-phase partitioning, precipitation, crystallization, monoliths and membrane chromatography--and their potential to do the unthinkable.

Purification of recombinant green fluorescent protein by three-phase partitioning

The technique of three-phase partitioning (TPP) was used to purify the green fluorescent protein (GFP) in a single step. TPP uses a combination of ammonium sulphate and tert-butanol to precipitate proteins from their crude extracts. In the first round of TPP with 20% ammonium sulphate saturation at the ratio of crude to tert-butanol 1:1 (v/v), most of the GFP remains in the lower aqueous phase. When subjected to a second round of TPP with 60% ammonium sulphate saturation at the ratio of crude to tert-butanol 1:2 (v/v) gives 78% recovery of GFP with a 20-fold purification. The sodium dodecyl sulphate-polyacrylamide gel electrophoretic (SDS-PAGE) analysis of purified preparation shows single band. The fluorescence excitation and emission spectra agreed with values reported in literature.

Separation of enzymes by sequential macroaffinity ligand-facilitated three-phase partitioning

Pectinase and cellulase were separated from a commercial enzyme preparation called Pectinex Ultra SP-L. This was carried out using a process called macroaffinity ligand-facilitated three-phase partitioning (MLFTPP). In this method, a water-soluble polymer is floated as an interfacial precipitate by adding ammonium sulfate and tert.-butanol. The polymer (appropriately chosen) in the presence of an enzyme for which it shows affinity, selectively binds to the enzyme and floats as a polymer-enzyme complex. In the first step, pectinase was purified (with alginate as the polymer) 13-fold with 96% activity recovery. In the second MLFTPP step, using chitosan, cellulase was purified 16-fold with 92% activity recovery. Both preparations showed a single band on sodium dodecylsulfate-polyacrylamide gel electrophoresis. This illustrative example shows that the strategy of sequential MLFTPP can be used to separate important biological activities from a crude broth.

Macroaffinity ligand-facilitated three-phase partitioning for purification of glucoamylase and pullulanase using alginate

Starch-degrading enzymes glucoamylase (from Aspergillus niger), and pullulanase (from Bacillus acidopullulyticus) were purified using alginates (polysaccharides consisting of mannuronic acids and guluronic acids) by a recently developed technique called macroaffinity ligand-facilitated three-phase partitioning (MLFTPP). In this process, a crude preparation of the enzyme was mixed with alginate. On addition of appropriate amounts of ammonium sulfate and t-butanol, the alginate bound enzyme appeared as an interfacial precipitate between the lower aqueous and the upper t-butanol phase. Enzyme activity from this interfacial precipitate was recovered using 1M maltose. Glucoamylase and pullulanase were purified 20- and 38-fold with 83% and 89% activity recovery, respectively. Both the purified preparations showed a single band on SDS-PAGE.

Three phase partitioning for extraction of oil from soybean

Three phase partitioning, a method generally used for protein separation, has been evaluated for extraction of oil from soybean. 82% oil was extracted within 1 h using this process which required simultaneous addition of t-butanol (1:1, v/v) and 30% ammonium sulphate to the soybean slurry.