GST 柱纯化 GSTrap FF

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GE Healthcare

Instructions 71-5016-96 AK

HiTrap affinity columns

GSTrap FF, 1 ml and 5 ml

GSTrap™ FF columns are prepacked 1 ml and 5 ml HiTrap™ columns for convenient, one-step purification of glutathione S-transferase (GST) tagged proteins produced using the pGEX series of expression vectors, other glutathione S-transferases and glutathione binding proteins.

GST-tagged proteins can be purified directly from pretreated bacterial lysates using GSTrap FF. Tagged proteins are eluted under mild, nondenaturing conditions that preserve protein antigenicity and function.

The medium, Glutathione Sepharose™ 4 Fast Flow, is also available as lab packages and is an excellent choice for scale-up.

The columns can be operated with a syringe, peristaltic pump or liquid chromatography system such as ÄKTAdesign™ or FPLC™ System.

Code No. 17-5130-01 17-5130-02 17-5130-05 17-5131-01 17-5131-02 17-5131-05

Product GSTrap FF GSTrap FF GSTrap FF GSTrap FF GSTrap FF GSTrap FF

No. supplied5 × 1 ml2 × 1 ml100 × 1 ml*1 × 5 ml5 × 5 ml100 × 5 ml*

* Special package delivered on specific customer order.

Connectorkit

Connectors supplied 1/16” male/luer female

Tubing connector flangeless/M6 female Tubing connector flangeless/M6 male Union 1/16” female/ M6 male

Union M6 female/ 1/16” male

Stop plug female, 1/16”

Usage

Connection of syringe to top of HiTrap column

Connection of tubing (e.g. Peristaltic Pump P1) to bottom of HiTrap column* Connection of tubing (e.g. Peristaltic Pump P1) to top of HiTrap column** Connection to original FPLC System through bottom of HiTrap column Connection to original FPLC System through top of HiTrap column Sealing bottom of HiTrap column

No. supplied

11111 2, 5 or 7

* Union 1/16” female/M6 male is also needed.** Union M6 female/1/16” male is also needed.

Tables of contents

1. Description 2. Operation 3. Scaling up 4. Storage

5. Cleavage of GST-tagged proteins 6. Troubleshooting guide 7. References

8. Ordering information p. 󰀲

3 5 7 7 7121718

1. Description

Medium properties

Glutathione Sepharose 4 Fast Flow is designed for purification of

glutathione S-transferase (GST) tagged proteins produced using the pGEX series of expression vectors (1), other glutathione S-transferases and

glutathione binding proteins. GST-tagged proteins can be purified directly from pretreated bacterial lysates with a one-step method using GSTrap FF. The tagged proteins are eluted under mild, non-denaturing conditions that preserve protein antigenicity and function. The glutathione ligand is coupled via a 10-carbon linker to highly cross-linked 4% agarose. The coupling is optimized to give high binding capacity for GST-tagged proteins and other glutathione binding proteins.

The total binding capacity is approximately 10 mg recombinant GST/ml

medium. The dynamic binding capacity will vary depending on the flow rate and the sample. If removal of the GST-tag (a naturally occurring Mr 26 000 protein) is required, the tagged protein can be digested with the appropriate site-specific protease while bound to GSTrap FF or, alternatively, after elution. Cleavage on GSTrap FF eliminates the extra step of separating the released protein from GST, since the GST-tag remains bound. The target protein is eluted using binding buffer.

Column

The columns are made of polypropylene, which is biocompatible and non-interactive with biomolecules. The columns have porous top and bottom frits that allow high flow rates. The columns are delivered with a stopper on the inlet and a snapoff end on the outlet. The separation can be easily achieved using a syringe together with the supplied adaptor, a pump, or a chromatography system such as ÄKTA™ or FPLC.

Note: To prevent leakage it is essential to ensure that the adaptor is tight.

Several columns can be connected in series to increase binding capacity. (Backpressure will increase).The column cannot be opened or refilled.

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The characteristics of GSTrap FF are summarized below.Table 󰀲. GSTrap FF characteristics

Column dimensions (i.d. × h) Column volumes Ligand

Ligand concentration Binding capacity*

Dynamic binding capacity*

Average particle size Bead structure

Maximum back pressure Maximum flow rate

Recommended flow rates*

Washing and elution: Chemical stability

pH stability

Storage temperature Storage

0.7 × 2.5 cm (1 ml) and 1.6 × 2.5 cm (5 ml)1 ml and 5 ml respectively

Glutathione and 10-carbon linker arm120–320 µmol glutathione/ml medium≈ 10 mg recombinant glutathione S-transferase/ml medium GST, Mr 26 000≈ 11 mg GST-tagged protein/ml mediumMr 43 000 (GSTrap FF 1 ml at 1 ml/min)90 µm

Highly cross-linked 4% agarose0.3 MPa, 3 bar

4 ml/min and 15 ml/min for 1 and 5 mlcolumns respectively

Sample loading: 0.2–1 ml/min (1 ml ) and 1–5 ml (5 ml)

1–2 ml/min (1 ml) and 5–10 ml/min (5 ml)All commonly used aqueous buffers, e.g. 1 M acetate pH 4.0 and 6 M guanidine

hydrochloride for 1 hour at room temperaturepH 3–12

+ 4 to + 30 °C20 % ethanol

*Note: Binding of GST to glutathione is flow dependent and lower flow rates often increase

the binding capacity. This is important during sample loading and elution. Protein characteristics, pH and temperature may also affect the binding capacity.

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2. Operation

The columns can be operated with a syringe, peristaltic pump or a liquid chromatography system.

Buffer preparation

Water and chemicals used for buffer preparation should be of high purity. We recommend filtering the buffers by passing them through a 0.45 µm filter before use.

Binding buffer: PBS, pH 7.3 (140 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 1.8 mM KH2PO4, pH 7.3)Elution Buffer:

50 mM Tris-HCl, 10 mM reduced glutathione, pH 8.0

Note: 1–10 mM DTT can be included in the binding and elution buffers.

Sample preparation

The sample should be centrifuged and/or filtered through a 45 µm filter immediately before it is applied to the column. If the sample is too viscous, dilute it with binding buffer to prevent clogging the column.

Purification

1. Fill the pump tubing or syringe with binding buffer. Connect the column

to the syringe (use the adaptor supplied) or pump tubing “drop to drop” to avoid introducing air into the column.2. Remove the snap-off end at the column outlet.

3. Equilibrate the column with 5 column volumes of binding buffer.4. Apply the sample using a syringe fitted to the luer adaptor or by

pumping it onto the column. For best results, use a flow rate of 0.2–1 ml/min (1 ml column) and 1–5 ml/min (5 ml column) during sample application.

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5. Wash with 5–10 column volumes of binding buffer or until no material

appears in the effluent. A flow rate of 1–2 ml/min (1 ml column) and 5–10 ml/min (5 ml column) is recommended for washing.6. Elute with 5–10 column volumes of elution buffer. A flow rate of

1–2 ml/min (1 ml column) and 5–10 ml/min (5 ml column) is recommended for elution.

Note: • One of the most important parameters affecting the binding

of GST-tagged proteins or other glutathione binding proteins to GSTrap FF is the flow rate. Due to the relatively slow binding kinetics between GST and glutathione, it is important to keep the flow rate low during sample application for maximum binding capacity. Protein characteristics, pH and temperature are other factors that may affect the binding capacity.

• Volumes and times used for elution may vary among fusion

proteins. Additional elutions with higher concentrations of glutathione may be required. Flowthrough, wash and eluted material from the column should be monitored for GST-tagged proteins using SDS-PAGE in combination with Western Blot if necessary.

• The GST Detection Module can be used to optimize conditions for

elution or to trace steps in the purification of a GST-tagged protein. The Module is designed to identify GST-tagged proteins using either a biochemical or an immunological assay.

• The concentration of GST-tagged protein can be estimated

by measuring the absorbance at 280 nm. The GST-tag can be approximated using the conversion; A280 ≈ 1 corresponds to ~ 0.5 mg/ml.

• The concentration of GST-tagged protein may also be determined

by standard chromogenic methods (e.g. Lowry, BCA, and Bradford assays). If Lowry or BCA assays are to be used, the sample must first be buffer exchanged using a HiTrap Desalting 5 ml column, a HiPrep™ 26/10 Desalting column or dialysed against PBS to remove glutathione, which can interfere with the protein measurement. The Bradford method can be used in the presence of glutathione.p. 6

• The reuse of GSTrap FF depends on the nature of the sample and should only be performed with identical samples to prevent cross-contamination.

Cleaning GSTrap FF

If the medium appears to be losing binding capacity, it may be due to an accumulation of precipitate, denatured or nonspecifically bound proteins.Removal of precipitated or denatured substances:

• Wash with 2 column volumes of 6 M guanidine hydrochloride,

immediately followed by 5 column volumes of PBS.Removal of hydrophobically bound substances:

• Wash with 3–4 column volumes of 70% ethanol or 2 column volumes of

1% Triton™ X-100 immediately followed by 5 column volumes of PBS.

3. Scaling up

For quick scale-up of purifications, two or three GSTrap FF can be connected in series (backpressure will increase). Further scaling up is easy using the 20 ml prepacked GSTPrep™ FF 16/10 column or bulk media packages.

4. Storage

Store the column at +4 to 30 °C in 20% ethanol.

5. Cleavage of GST-tagged proteins

If removal of the GST-tag is necessary, tagged proteins containing a PreScission™ Protease recognition site, a thrombin recognition site or a

factor Xa recognition site may be cleaved either while bound to GSTrap FF or in solution after elution. Cleavage after elution is suggested if optimization of cleavage conditions is necessary. Samples can easily be removed at various time points and analyzed by SDS-PAGE to estimate the yield, purity and extent of digestion. The amount of protease used, the temperature and the length of incubation required for complete digestion may vary

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depending on the fusion partner. Optimal conditions for each fusion should be determined in pilot experiments, e.g. incubation time may be reduced by using higher concentrations of proteolytic enzyme.

1. PreScission Protease

PreScission Protease, Mr 46 000

PreScission cleavage buffer: 50 mM Tris-HCl, 150 mM NaCl,1 mM EDTA, 1 mM dithiothreitol (DTT), pH 7.5

PreScission Protease cleavage of GST-taggedprotein bound to GSTrap FF

Assumption: 8 mg GST-tagged protein bound/ml medium1. Follow steps 1–5 under “Purification”, (see p. 5).

2. Wash GSTrap FF with 10 column volumes of PreScission cleavage buffer.3. Prepare the PreScission Protease mix:

GSTrap FF 1 ml column (8 mg GST-tagged protein bound): Mix 80 µl (160 units) of PreScission Protease with 920 µl of PreScission cleavage buffer at +4 °C.

GSTrap FF 5 ml column (40 mg GST-tagged protein bound): Mix 400 µl (800 units) of PreScission Protease with 4.6 ml of PreScission cleavage buffer at +4 °C.

4. Load the PreScission Protease mix onto the column using a syringe and

the adaptor supplied.

Seal the column with the top and bottom stop plugs supplied.5. Incubate the column at +4 °C for 4 hours.

6. Fill a syringe with 3 ml (1 ml column) or 15 ml (5 ml column) of PreScission

cleavage buffer. Remove the top and bottom stop plugs. Avoid

introducing air into the column. Elute the column and collect the eluate (0.5 ml-1 ml/tube). The eluate will contain the protein of interest, while the GST moiety of the tagged protein and the PreScission Protease will remain bound to GSTrap FF.

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PreScission Protease cleavage of eluted GST-tagged protein

Assumption: 8 mg GST-tagged protein bound/ml medium1. Follow steps 1–6 under “Purification”, (see page 5).

2. Remove the reduced glutathione from the eluate using a quick buffer

exchange on HiTrap Desalting, a PD-10 column or HiPrep 26/10 Desalting depending on the sample volume, or dialyse against PreScission cleavage buffer.3. Add 1 µl (2 U) of PreScission Protease for each 100 µg of tagged protein

in the eluate. If the amount of tagged protein in the eluate has not been determined, add 80 µl (160 units) of PreScission Protease (tagged protein eluted from GSTrap FF 1 ml column) or 400 µl (800 units) of PreScission Protease (tagged protein eluted from GSTrap FF 5 ml column).4. Incubate at +4 °C for 4 hours.

5. Once digestion is complete, apply the sample to an equilibrated GSTrap

FF column to remove the GST moiety of the tagged protein and the PreScission Protease. The protein of interest will be found in the flow-through, while the GST moiety of the tagged protein and the PreScission Protease will remain bound to GSTrap FF.

󰀲. Thrombin

Thrombin, Mr 37 000

Thrombin cleavage buffer: PBS, pH 7.3

Preparation of thrombin solution:

1. Dissolve 500 U thrombin in cold 500 µl PBS (1 U/µl).2. Swirl gently to dissolve.

3. Freeze as 80 µl aliqouts and keep at –80 °C.

Thrombin cleavage of GST-tagged protein bound to GSTrap FF

Assumption: 8 mg GST-tagged protein bound/ml medium1. Follow steps 1–5 under “Purification”, (see p. 5).

2. Prepare the thrombin mix: GSTrap FF 1 ml column (8 mg GST fusion

protein bound): Mix 80 µl thrombin solution (1 U/µl ) with 920 µl PBS.

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GSTrap FF 5 ml column (40 mg GST-tagged protein bound): Mix 400 µl thrombin solution with 4.6 ml PBS.

3. Load the thrombin solution onto the column using a syringe and the

adaptor supplied. Seal the column with the top and bottom plugs supplied.4. Incubate the column at room temperature (+22 to +25 °C) for 2–16 hours.5. Fill a syringe with 3 ml (1 ml column) or 15 ml (5 ml column) PBS. Remove

the top and bottom stop plugs from the column. Avoid introducing air into the column. Elute the column and collect the eluate (0.5 ml-1 ml/tube). The eluate will contain the protein of interest and thrombin, while the GST moiety of the tagged protein will remain bound to GSTrap FF.Note: After cleavage using thrombin the enzyme can be removed from

eluted protein using HiTrap Benzamidine FF (high sub), see ordering information.

Thrombin cleavage of eluted GST-tagged protein

Assumption: 8 mg GST-tagged protein bound/ml medium1. Follow steps 1–6 under “Purification”, (see p. 5).

2. Add 10 µl (10 units) of thrombin solution for each mg of tagged protein

in the eluate. If the amount of tagged protein in the eluate has not been determined, add 80 µl (80 U) thrombin solution (tagged protein eluted from GSTrap FF 1 ml column) or 400 µl (400 U) thrombin solution (tagged protein eluted from GSTrap FF 5 ml column).3. Incubate at room temperatue (+22 to 25 °C) for 2–16 hours.

4. Once digestion is complete, GST can be removed by first removing

glutathione using a quick buffer exchange on HiTrap Desalting, a PD-10 column or HiPrep 26/10 Desalting depending on the sample volume, or dialysing against PBS. Then apply the sample to an equilibrated GSTrap FF column. The purified protein of interest and thrombin will be found in the flow-through.Note: After cleavage using thrombin the enzyme can be removed from

eluted protein using HiTrap Benzamidine FF (high sub), see ordering information.p. 10

󰀳. Factor Xa

Factor Xa, Mr 48 000

Note: Factor Xa consists of two subunits linked by disulfide bridges. As

glutathione can disrupt disulfide bridges, it should be removed from the sample prior to the cleavage reaction.Factor Xa cleavage buffer: 50 mM Tris-HCl, 150 mM NaCl, 1 mM CaCl2, pH 7.5Preparation of factor Xa solution:

1. Dissolve 400 U factor Xa in 400 µl cold water (1 U/µl).2. Swirl gently to dissolve.

3. Freeze as 80 µl aliqouts and keep at –80°C.

Factor Xa cleavage of GST-tagged protein bound to GSTrap FF

Assumption: 8 mg GST-tagged protein bound/ml medium1. Follow steps 1–5 under “Purification”, (see p. 5).

2. Wash GSTrap FF with 10 column volumes of factor Xa cleavage buffer.3. Prepare the factor Xa mix:

GSTrap FF 1 ml column (8 mg GST-tagged protein bound): Mix 80 µl factor

Xa solution with 920 µl factor Xa cleavage buffer.

GSTrap FF 5 ml column (40 mg GST-tagged protein bound): Mix 400 µl factor Xa solution with 4.6 ml factor Xa cleavage buffer.

4. Load the mix onto the column using a syringe and the adaptor supplied. Seal the column with the top and bottom stop plugs supplied.

5. Incubate the column at room temperature (+22 to 25 °C) for 2–16 hours.6. Fill a syringe with 3 ml (1 ml column) or 15 ml (5 ml column) factor

Xa cleavage buffer. Remove the top and bottom stop plugs from the column. Avoid introducing air into the column. Elute the column and collect the eluate (0.5 ml-1 ml/tube). The eluate will contain the protein of interest and factor Xa, while the GST moiety of the tagged protein will remain bound to GSTrap FF.

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Note: After cleavage using factor Xa the enzyme can be removed from

eluted protein using HiTrap Benzamidine FF (high sub), see ordering information.

Factor Xa cleavage of eluted GST-tagged protein

Assumption: 8 mg GST-tagged protein bound/ml medium1. Follow steps 1–6 under “Purification”, (see p. 5).

2. Remove the reduced glutathione from the eluate using a quick buffer

exchange on HiTrap Desalting, a PD-10 column or HiPrep 26/10 Desalting depending on sample volume, or dialyse against factor Xa cleavage buffer.3. Add 10 units of factor Xa solution for each mg tagged protein in the

eluate. If the amount of tagged protein in the eluate has not been determined, add 80 µl (80 units) of factor Xa solution (eluted tagged protein from GSTrap FF 1 ml column) or 400 µl (400 units) of factor Xa solution (eluted tagged protein from GSTrap FF 5 ml column).4. Incubate the column at room temperature (+22 to 25 °C) for 2–16 hours.5. Once digestion is complete, apply the sample to an equilibrated GSTrap

FF column to remove the GST moiety . The protein of interest will be found in the flow-through together with factor Xa.Note: After cleavage using factor Xa the enzyme can be removed from

eluted protein using HiTrap Benzamidine FF (high sub), see ordering information.

6. Troubleshooting guide

Consult the GST Gene Fusion System Handbook (1) for more detailed information and pGEX instructions regarding troubleshooting recommendations for expression, fermentation and solubilization.

GST-tagged protein does not bind to GSTrap FF

• GST-tagged protein denatured by sonication: Too extensive sonication

can denature the tagged protein and prevent it binding to GSTrap FF. Use mild sonication conditions during cell lysis.p. 1󰀲

• Add DTT prior to cell lysis: Adding DTT to a final concentration of

1–10 mM prior to cell lysis may significantly increase binding of some GST-tagged proteins to GSTrap FF.• Test the binding of GST from parental pGEX: Prepare a sonicate of cells

harboring the parental pGEX plasmid and check binding to the matrix. If GST produced from the parental plasmid binds with high affinity, the fusion partner may have altered the conformation of GST, thereby reducing its affinity. Adequate results may be obtained by reducing the temperature used for binding to +4°C, and by limiting column washing.• Equilibrate GSTrap FF before use: Binding of GST-tagged proteins to

GSTrap FF is not efficient at pH less than 6.5 or greater than 8. Check that the GSTrap FF column has been equilibrated with a buffer pH 6.5 to 8.0 (e.g. PBS) before the cell lysate is applied.• Use a fresh GSTrap FF: If the GSTrap FF column has already been used

several times, it may be necessary to use a new GSTrap FF column. See also “Cleaning GSTrap FF”.• Decrease flow rate during sample load, see note p. 6.

GST-tagged protein is not eluted efficiently from GSTrap FF

• Increase the time used for elution: Decrease the flow during elution.• Increase the volume of elution buffer: Sometimes, especially after

on-column cleavage of fusion protein, a larger volume of buffer may be necessary to elute the fusion protein.• Increase the concentration of glutathione in the elution buffer: The

10 mM recommended in this protocol should be sufficient for most applications, but exceptions exist. Try 50 mM Tris- HCl, 20–40 mM reduced glutathione, pH 8.0 as elution buffer.• Increase the pH of the elution buffer: A low pH may limit elution from

GSTrap FF. Increasing the pH of the elution buffer to pH 8–9 may improve elution without requiring an increase in the concentration of glutathione used for elution.• Increase the ionic strength of the elution buffer: Adding 0.1–0.2 M NaCl

to the elution buffer may also improve results.

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• Add a non-ionic detergent to the elution buffer: Non-specific

hydrophobic interactions may prevent solubilization and elution of fusion proteins from GSTrap FF. Adding a non-ionic detergent may improve results. Adding 0.1% Triton X-100 or 2% N-octylglucosid can significantly improve elution of some GST-tagged proteins.

Multiple bands are observed after electrophoresis/Western Blotting analysis of eluted target protein

• Mr 70 000 protein co-purifies with the GST-tagged protein:

The Mr 70 000 protein is probably a protein product of the E. coli gene

dnaK. This protein is involved in protein folding in E. coli. It has been

reported that this association can be disrupted by incubating the fusion protein in 50 mM Tris-HCl, 2 mM ATP, 10 mM MgSO4, pH 7.4 for 10 min. at +37 °C prior to loading on GSTrap FF.Alternatively, remove the DnaK protein by passing the tagged protein solution through ATP-agarose or by ion exchange.

• Add a protease inhibitor: Multiple bands may be a result of partial

degradation of tagged proteins by proteases. Adding 1 mM PMSF to the lysis solution may improve results. A nontoxic, water-soluble alternative to PMSF is 4-(2-aminoethyl)-benzenesulfonyl fluoride hydrochloride (AEBSF), commercially available as Pefabloc™ SC from Boehringer Mannheim.Note: Serine protease inhibitors must be removed prior to cleavage by

thrombin or factor Xa. PreScission Protease is not a consensus serine protease and is insensitive to many of the protease inhibitors tested at GE Healthcare.• Use a protease-deficient host: Multiple bands may be the result of

proteolysis in the host bacteria. If this is the case, the use of a host-deficient strain may be required (e.g. lon- or ompT). E. coli BL21 is provided with the pGEX vectors. This strain is ompT.• Decrease sonication: Cell disruption is apparent by partial clearing of

the suspension and can be checked by microscopic examination. Adding lysozyme (0.1 volume of a 10 mg/ml lysozyme solution in 25 mM Tris-HCl, pH 8.0) prior to sonication may improve results. Avoid frothing as this p. 1󰀴

may denature the fusion protein. Over-sonication can also lead to the co-purification of host proteins with the GST-tagged protein.

• Include an additional purification step: Additional bands may

be caused by the co-purification of a variety of proteins known as chaperonins, which are involved in the correct folding of nascent proteins in E. coli. These include, but may not be limited to: DnaK (Mr ~ 70 000), DnaJ (Mr ~ 37 000), GrpE (Mr ~ 40 000), GroEL (Mr ~ 57 000) and GroES (Mr ~ 10 000). Several methods for purifying GST-tagged proteins from these co-purifying proteins have been described.• Cross-adsorb antibody with E. coli proteins: Depending on the source

of the anti-GST antibody, it may contain antibodies that react with various E. coli proteins that may be present in your fusion protein sample. Cross-adsorb the antibody with an E. coli sonicate to remove anti-E. coli antibodies from the preparation. Anti-GST antibody from GE Healthcare has been cross-adsorbed against E. coli proteins and tested for its lack of non-specific background binding in Western Blots.

Incomplete cleavage of GST-tagged proteins

• The PreScission Protease, thrombin or factor Xa to tagged protein

ratios are incorrect: Check the amount of tagged protein in the

digestion. Note that the capacity of GSTrap FF for GST is approximately 10 mg/ml medium. In most purifications, however, the matrix is not saturated with tagged protein.Ratios: PreScission protease, at least 10 units/mg tagged protein.

Thrombin, at least 10 units/mg tagged protein. One cleavage unit of thrombin from GE Healthcare digests ≥ 90% of 100 µg of a test tagged protein in 16 hours at +22 °C.

Factor Xa, at least 1% (w/w) tagged protein. For some tagged proteins, up to 5% factor Xa can be used. The optimum amount must be determined empirically.

In some cases, a tagged protein concentration of 1 mg/ ml has been found to give optimal results. Adding ≤ 0.5% (w/v) to the reaction buffer can significantly improve factor Xa cleavage with some tagged proteins. Various concentrations of SDS should be tested to find the optimum concentration.

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• Increase incubation time and enzyme concentration: For PreScission

Protease, thrombin or factor Xa, increase the reaction time to 20 hours or more if the tagged protein is not degraded by extensive incubation. The amount of enzymes can also be increased.• Verify the presence of specific cleavage sites: Check the DNA sequence

of the construct. Compare it with a known sequence and verify that the different specific cleavage sites for the enzyme used have not been altered during the cloning of your tagged protein.

Ensure that cleavage enzyme inhibitors are absent

• PreScission Protease: Buffer exchange or dialyse the tagged protein

against 50 mM Tris-HCl, 150 mM NaCl, 1 mM EDTA, 1 mM DTT, pH 7.5 before cleavage.• Factor Xa: Buffer exchange on HiTrap Desalting, a PD-10 column or

HiPrep 26/10 Desalting depending on the sample volume, or dialyse against 50 mM Tris-HCl, 150 mM NaCl, 1 mM CaCl2, pH 7.5.• Factor Xa is not properly activated: Functional factor Xa requires

activation of factor X with Russell’s viper venom. Activation conditions are a ratio of Russell’s viper venom to factor Xa of 1% in 8 mM Tris-HCl, 70 mM NaCl, 8 mM CaCl2, pH 8.0. Incubate at +37 °C for 5 min. Factor Xa from GE Healthcare has been preactivated by this procedure.• The first amino acid after the factor Xa recognition sequence is Arg

or Pro: Check the sequence of the fusion partner to be sure that the first three nucleotides after the factor Xa recognition sequence do not code for Arg or Pro.

Multiple bands are observed on SDS gels following enzyme cleavage:

• Determine when the bands appear: Test to be certain that additional

bands are not present prior to PreScission Protease, thrombin or factor Xa cleavage. Such bands may be the result of proteolysis in the host bacteria.• Tagged partner may contain recognition sequences for PreScission

Protease, thrombin or factor Xa: Check the sequences. See the GST Gene Fusion System Handbook (1) for details.p. 16

7. References

1. GST Gene Fusion System Handbook, GE Healthcare, Code No. 18-1157-582. Rapid purification of GST-fusion proteins from large sample volumes.

Miniposter, 18-1139-51, GE Healthcare.3. Efficient, rapid protein purification and on-column cleavage using

GSTrap FF columns. Application Note, 18-1146-70, GE Healthcare.4. Purification of GST-fusion proteins, on-column cleavage and sample

clean-up. Miniposter, 18-1150-20, GE Healthcare.5. Dian, C., et al, J of chromatography B, 769 (1), 133–144 (2002)

6. Strategies for the purification and on-column cleavage of glutathione

S-transferase fusion target proteins. J of Chromatography B, 2002. 769(1): 133–144. Dian, C., et al.For more information about HiTrap columns and updated reference list for the use of GSTrap FF columns, (Code No. 18-1156-67) visitwww.gehealthcare.com/hitrap

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8. Ordering information

Prdouct GSTrap FF GSTrap FF GSTrap FF GSTrap FF GSTrap FF GSTrap FF Related products

Glutathione Sepharose 4 Fast Flow Glutathione Sepharose 4 Fast Flow Glutathione Sepharose 4 Fast Flow HiTrap Desalting HiTrap Desalting

HiTrap Benzamidine FF (high sub) HiTrap Benzamidine FF (high sub) HiTrap Benzamidine FF (high sub) PD-10 Desalting column HiPrep 26/10 Desalting HiPrep 26/10 Desalting GST Detection Module Anti-GST Antibody

No. Supplied 5 × 1 ml 2 × 1 ml 100 × 1 ml* 1 × 5 ml 5 × 5 ml 100 × 5 ml* No. Supplied 25 ml 100 ml 500 ml** 5 × 5 ml 100 x 5 ml* 5 × 1 ml 2 × 1 ml 1 × 5 ml 30

1 × 53 ml 4 × 53 ml 50 reactions 0.5 ml

Code No.17-5130-0117-5130-0217-5130-0517-5131-0117-5131-0217-5131-05Code No.17-5132-0117-5132-0217-5132-0317-1408-0111-0003-2917-5143-0117-5143-0217-5144-0117-0851-0117-5087-0117-5087-0227-4590-01 27-4577-01

* Special pack size delivered on specific customer order.

** Larger quantities are available. Please contact GE Healthcare for more information.

Site-Specific Proteases

Product

PreScission Protease Thrombin Factor Xa

No. Supplied 500 units 500 units 400 units

Code No.27-0843-0127-0846-0127-0849-01

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