阅读说明：本技术 一种固定化金属离子亲和色谱填料、色谱柱及其制备方法 (Immobilized metal ion affinity chromatographic packing, chromatographic column and preparation method thereof ) 是由 张文洋 晏石娟 黄文洁 吴绍文 殷志斌 孔谦 于 2021-06-15 设计创作，主要内容包括：本发明公开了一种固定化金属离子亲和色谱填料、色谱柱及其制备方法。将钾水玻璃、γ-缩水甘油醚氧丙基三甲氧基硅烷和水溶解的三磷酸腺苷二钠混合搅拌,然后加入用水溶解的甲酰胺搅拌获得反应液,反应固化获得固体材料,然后洗涤,获得固定化金属离子亲和色谱柱填料。本发明通过一步反应法制备的ATP修饰的固定化金属离子亲和毛细管整体柱,制备步骤简单快速、重复性和良品率高、制备成本低。仅需将原料混合均匀后经历一次烘烤反应便可得到,其物理化学稳定性好,多次使用后具有较好的重现性。(The invention discloses an immobilized metal ion affinity chromatographic packing, a chromatographic column and a preparation method thereof. Mixing and stirring potash water glass, gamma-glycidoxypropyltrimethoxysilane and water-soluble adenosine disodium triphosphate, adding water-soluble formamide, stirring to obtain a reaction solution, reacting and curing to obtain a solid material, and washing to obtain the immobilized metal ion affinity chromatographic column filler. The ATP-modified immobilized metal ion affinity capillary monolithic column prepared by the one-step reaction method has the advantages of simple and quick preparation steps, high repeatability and yield and low preparation cost. The material can be obtained by only one-time baking reaction after being uniformly mixed, and the material has good physical and chemical stability and better reproducibility after being used for multiple times.)

1.A preparation method of an immobilized metal ion affinity chromatographic column filler is characterized in that potash water glass, gamma-glycidoxypropyltrimethoxysilane and water-soluble adenosine disodium triphosphate are mixed and stirred, then water-soluble formamide is added and stirred to obtain a reaction solution, a solid material is obtained through reaction and solidification, and then the solid material is washed to obtain the immobilized metal ion affinity chromatographic column filler.

2. The method as claimed in claim 1, wherein the ratio of the potassium water glass, the gamma-glycidoxypropyltrimethoxysilane, the disodium adenosine triphosphate and the formamide is 500-2000:1-10:2-50: 20-130.

3. The preparation method according to claim 2, wherein the amount of the potash water glass, the gamma-glycidoxypropyltrimethoxysilane, the disodium adenosine triphosphate and the formamide are 1000:6:7.5:68 by mass.

4. The method of claim 1, wherein the potash water glass has a modulus in the range of 2 to 4 and a baume degree in the range of 20 to 50.

5. The method according to claim 4, wherein the potash water glass has a modulus of 3.3 and a baume degree of 40.

6. The method of claim 1, wherein the curing is at a temperature of 100 ℃ for 10 hours; the washing is carried out by washing with 1M ammonium nitrate, 0.1M nitric acid and water in sequence.

7. An immobilized metal ion affinity chromatography column packing prepared according to the preparation method of any one of claims 1 to 6.

8. A method for preparing an immobilized metal ion affinity chromatographic column, which is characterized in that the chromatographic column is inserted into the reaction solution in any one of claims 1 to 6, the chromatographic column is filled with the reaction solution, then the reaction solution of the filled chromatographic column is reacted and solidified, and then the immobilized metal ion affinity chromatographic column modified by ATP is obtained by washing.

9. The method of claim 8, wherein the chromatographic column is an elastic quartz capillary.

10. An ATP-modified immobilized metal ion affinity chromatography column prepared according to the preparation method of claim 8 or 9.

Technical Field

The invention belongs to the field of chromatography, and particularly relates to an immobilized metal ion affinity chromatography filler, a chromatographic column and a preparation method thereof.

Background

Immobilized metal ion affinity chromatography (IMAC) is used for affinity purification of proteins, enzymes, polypeptides, amino acids, and the like having binding ability to metal ions. The principle is that the electrostatic interaction between metal ions on a solid phase carrier and some amino acids or chemical modification groups exposed by proteins/polypeptides is utilized to enrich and purify specific proteins/polypeptides, and through the development of thirty years, the method becomes one of the most effective technologies for separating and purifying biomolecules such as proteins gradually.

The core of immobilized metal ion affinity chromatography (IMAC) lies in the selection and preparation processes of a solid phase matrix, a ligand and metal ions, the enrichment effect can be influenced by the conditions of loading, washing and elution, and the performance parameters mainly comprise selectivity, sensitivity, reproducibility, loading quantity, service life, application range and the like.

The solid phase matrix of the current commercial IMAC product is usually resin microspheres or magnetic particles, so as to carry out the procedures of loading, washing and elution by centrifugation or magnetic adsorption, and iminodiacetic acid (IDA), nitrilotriacetic acid (NTA) and ethylenediamine (TED) are representative chelating ligands for fixing metal ions, and carboxyl and amine groups of the chelating ligands can lead Al to react³⁺、 Fe^{3 +}、Ga³⁺、Ni²⁺The plasma metal ions are chelated on the surface of the solid phase matrix, but the combination has poor chelating performance and low selectivity. At present, IMAC materials, whether commercialized or reported in literature, are usually in the form of microspheres or magnetic materials, and are aimed in a centrifugal tubeThe standard protein/polypeptide enrichment, the processes of loading, washing and elution are all carried out manually, which is time-consuming and labor-consuming, and in addition, the current commercialized IMAC material is monopolized by foreign companies and is expensive (such as Saimei flying cargo number A32992, 4629 yuan 30 times).

Disclosure of Invention

The first purpose of the invention is to provide an immobilized metal ion affinity chromatographic column filler which is loose and porous, has high specific surface area, low back pressure, good physical and chemical stability, good mechanical stability, high selectivity, high sensitivity and high enrichment factor.

The immobilized metal ion affinity chromatographic column filler is prepared by the following method:

mixing and stirring potash water glass, gamma-glycidoxypropyltrimethoxysilane and water-soluble adenosine disodium triphosphate, adding water-soluble formamide, stirring to obtain a reaction solution, reacting and curing to obtain a solid material, and washing to obtain the immobilized metal ion affinity chromatographic column filler.

The preparation principle of the immobilized metal ion affinity chromatographic column filler is shown as follows:

1. preparation of potash water glass

mKOH+_nSiO₂→mK₂O·(n-m)SiO₂+mH₂O

2. Hydrolysis of potassium water glass in formamide under heating condition

3. Simultaneous with step 2, the silicon coupling agent and ATPNa₂The reaction of (1):

4. ATP modification on silica gel substrates

5. The filler plays an enrichment function

Preferably, the first and second liquid crystal materials are,

s1, uniformly mixing potassium water glass and gamma-glycidyl ether oxypropyl trimethoxy silane to obtain a mixed solution of S1;

s2, dissolving the adenosine disodium triphosphate in water, and adding the solution into the mixed solution of S1 to obtain a mixed solution of S2;

and S3, dissolving formamide in water, adding the dissolved formamide into the mixed solution of S2, stirring to obtain a reaction solution, reacting to obtain a solid material, and washing to obtain the immobilized metal ion affinity chromatographic column filler.

Preferably, the modulus range of the potash water glass is 2-4, and the Baume degree range is 20-50. Further preferably, the potash water glass has a modulus of 3.3 and a baume degree of 40.

Preferably, the curing is at a temperature of 100 ℃ for 10 hours.

Preferably, the washing is with 1M ammonium nitrate, 0.1M nitric acid and water sequentially.

Preferably, the using amount mass ratio of the potash water glass, the gamma-glycidoxypropyltrimethoxysilane, the adenosine triphosphate disodium salt and the formamide is 500-2000:1-10:2-50: 20-130. Further preferably 1000:6:7.5: 68.

The second purpose of the invention is to provide a preparation method of an immobilized metal ion affinity chromatographic column, which is prepared by the following steps:

inserting a chromatographic column into the reaction solution, filling the chromatographic column with the reaction solution, reacting and solidifying the reaction solution of the filled chromatographic column, and washing to obtain the ATP modified immobilized metal ion affinity chromatographic column.

The chromatographic column is a capillary tube, such as an elastic quartz capillary tube (with the outer diameter of 360 micrometers, the inner diameter of 150 micrometers and the length of 15 centimeters), and the ATP modified immobilized metal ion affinity capillary monolithic column is prepared.

The immobilized metal ion affinity chromatographic column filler has the advantages of looseness, porosity, high specific surface area, low back pressure, good physical and chemical stability, good mechanical stability, high selectivity, high sensitivity and high enrichment multiple.

The ATP-modified immobilized metal ion affinity capillary monolithic column prepared by the one-step reaction method has the advantages of simple and quick preparation steps, high repeatability and yield and low preparation cost. The material can be obtained by only one-time baking reaction after being uniformly mixed, and the material has good physical and chemical stability and better reproducibility after being used for multiple times. Compared with the enrichment material in the form of microspheres or magnetic materials commonly used in the field, the ATP-modified immobilized metal ion affinity capillary monolithic column has the potential of being used with a nano-upgrading liquid phase system, can automatically perform labor-intensive operations of metal ion loading, sample loading, washing, elution and the like by combining an automatic sample feeding system, and simultaneously achieves the level of superior level in the industry on site coverage, detection limit and selectivity of phosphorylated peptide.

Drawings

FIG. 1 is a cross-sectional electron microscope image of ATP-modified immobilized metal ion affinity capillary monolithic column, which is 200 μm and 5 μm in scale, respectively.

FIG. 2 is a first-order mass spectrum diagram of the ATP modified immobilized metal ion affinity capillary monolithic column for enriching phosphorylated peptides in an alpha-casein enzyme digestion product.

FIG. 3 is a first-order mass spectrum of the ATP modified immobilized metal ion affinity capillary monolithic column enriched with phosphorylated peptides in 0.2ng and 2ng of alpha-casein enzyme digestion products.

FIG. 4 is a first-order mass spectrum of phosphorylated peptide in ATP modified immobilized metal ion affinity capillary monolithic column enriched with 2ng of alpha-casein and 2. mu.g of BSA enzyme digestion product.

Detailed Description

The present invention will be further described with reference to specific examples, which are provided for the purpose of illustration only and are not intended to limit the scope of the present invention in any way. The design idea of the present invention or simple substitution of the same should be included in the protection scope of the present invention. Reagents, materials, methods and apparatus used in the present invention are all conventional in the art unless otherwise indicated.

Example 1 preparation of ATP-modified immobilized Metal ion affinity capillary monolithic column

The invention relates to an ATP (adenosine triphosphate) modified immobilized metal ion affinity capillary monolithic column prepared by a one-step reaction method, which specifically comprises the following steps:

s1. Add 740. mu.l (about 1000mg) of potassium water glass (modulus 3.3, baume 40) to a microreactor, add 6. mu.l (about 6mg) of gamma-glycidoxypropyltrimethoxysilane (GLYMO, Cas No.: 2530-83-8) slowly with stirring at room temperature, and stir well for 30 minutes at room temperature.

S2, weighing 7.5mg of disodium adenosine triphosphate, dissolving the disodium adenosine triphosphate with 160 microliters of deionized water, slowly adding the disodium adenosine triphosphate into the reaction liquid obtained in the step S1, and continuously and fully stirring the disodium adenosine triphosphate for 30 minutes at room temperature.

S3, taking 60 microliters (about 68mg) of formamide, uniformly mixing with 40 microliters of deionized water, slowly adding the mixture into the reaction liquid obtained in the step S2, and continuously stirring for 1 minute at room temperature to obtain the reaction liquid.

S4, cutting a batch of elastic quartz capillary tubes with the outer diameter of 360 micrometers, the inner diameter of 150 micrometers and the length of 15 centimeters, inserting the elastic quartz capillary tubes into the reaction liquid obtained in the S3, and filling the capillary tubes with the reaction liquid by utilizing the capillary phenomenon.

S5, placing the filled capillary tube into a 100 ℃ oven for curing for 10 hours, and cutting off 2 cm from two ends of the obtained monolithic column respectively.

S6, washing the monolithic column by using a pressure injection pool and sequentially using 200 microliters of 1M ammonium nitrate, 0.1M nitric acid and deionized water respectively to obtain the finished product of the ATP modified immobilized metal ion affinity capillary monolithic column.

The section of the ATP-modified immobilized metal ion affinity capillary monolithic column is shown in an electron microscope picture of attached figure 1, under a visual field scale of 5 micrometers, the material can be observed to be in a loose porous shape, the average pore diameter is about 1 micrometer, and the material is proved to have a large specific surface area which is the basis for high enrichment efficiency.

Example 2 the ATP-modified immobilized metal ion affinity capillary monolithic column prepared in example 1 of the present invention was examined for its ability to enrich for phosphorylated peptides.

The ATP-modified immobilized metal ion affinity capillary monolithic column prepared in the embodiment 1 is used for enriching phosphorylated peptides obtained by treating standard phosphorylated protein alpha-casein or BSA with trypsin. The enrichment performance of the strain is inspected from the aspects of site coverage, detection limit, selectivity and the like.

2mg/ml BSA dissolved in 50mM ammonium bicarbonate solution was heated at 56 ℃ for 30min by adding DTT to 10mM, and incubated in the dark for 40min by adding iodoacetamide to 40mM to break the disulfide bonds. 1mg of standard phosphorylated protein alpha-casein and 1mg of disulfide bond-broken BSA were dissolved in 1mL of 50mM ammonium bicarbonate, and treated with 20. mu.g of trypsin for 8 hours, respectively, to obtain two kinds of 1mg/mL protease digests. (Standard phosphorylated protein alpha-casein contains two kinds of phosphorylated proteins, alpha-S1-casein and alpha-S2-casein, 9 and 10 phosphorylation sites are reported, after trypsin treatment, a series of monophosphorylated peptide, polyphosphorylated peptide and non-phosphorylated peptide can be generated, and signals of the non-phosphorylated peptide are mainly observed in a mass spectrum without specific enrichment; bovine serum albumin BSA is a common protein, does not have phosphorylation sites and generates a plurality of non-phosphorylated peptides after trypsin treatment)

The method comprises the following specific steps:

s1, pushing 100 microliters of a solution containing 80% acetonitrile and 1% TFA in volume fraction to flow through an ATP-modified immobilized metal ion affinity capillary monolithic column (hereinafter referred to as monolithic column) by using a micro-injection pump to finish cleaning.

S2, pushing 100 microliters of 0.1M zirconium chloride solution to flow through the monolithic column by using a micro-injection pump to finish Zr pairing⁴⁺And (4) fixing.

S3, a certain amount of protease cuttings (the site coverage rate experiment is 2 mug alpha-casein enzyme cuttings \100pmol, the detection limit experiment is 0.2ng alpha-casein enzyme cuttings \10fmol or 2ng alpha-casein enzyme cuttings \100fmol, the selectivity experiment is 2ng alpha-casein enzyme cuttings and 2 mug BSA enzyme cuttings) are dissolved in 100 microliter volume fraction 80% acetonitrile and 1% TFA solution, and the solution is pushed to flow through the monolithic column by using a micro-injection pump to complete the enrichment of phosphorylated peptide.

S4, pushing 100 microliters of 80% acetonitrile and 1% TFA solution with volume fraction to flow through the monolithic column by using a micro-injection pump to complete the cleaning of the non-specifically bound polypeptide.

S5, connecting the tail end of the monolithic column with an elastic quartz capillary, a nano spray needle, a nano ESI ion source and an Orbitrap Fusion mass spectrum, continuously pushing 5% ammonia water by using a micro-injection pump according to the flow rate of 0.5 microliter/min, eluting the phosphorylated peptide enriched by the monolithic column, and detecting the eluted product in real time by using a mass spectrum.

TABLE 1 identification of ATP-modified immobilized metal ion affinity capillary monolithic column enriched for alpha-casein enzyme cleavage phosphorylated peptide

Experimental results show that the ATP modified immobilized metal ion affinity capillary monolithic column prepared by the invention has an enrichment effect on both mono-phosphorylated peptide and poly-phosphorylated peptide (figure 2), the site coverage rates of alpha-casein-S1 and alpha-casein-S2 (the standard product contains the two alpha-casein proteins) are respectively up to 100% and 90% (table 1), the detection limit of the enrichment of phosphorylated peptide is up to 10fmol (figure 3), the selectivity of phosphorylated peptide is up to 1:1000 (alpha-casein: BSA) (1ug alpha-casein and 1mg BSA mixture) (figure 4), and the level of industrial circulation is reached.