A preparation method of nonapeptide-1

Abstract

The present invention provides a preparation method of nonapeptide 1, first synthesizes nonapeptide 1 crude product by solid phase synthesis method, then adopts modified polysulfone filter membrane, reversed-phase polymer column and weak anion exchange column to be combined to purify, greatly improves purification efficiency. The present invention, by controlling the consumption of acylating agent, makes modified polysulfone filter membrane reach the effect of partial hydrophilic modification, retains a large amount of amino groups while amide groups are grafted on the filter membrane surface and micropore, greatly enhances the compatibility of modified polysulfone filter membrane and polypeptide, enhances the permeability of polypeptide molecule, can quickly and efficiently separate polypeptide molecule from impurities, thus improves the recovery rate of polypeptide;Meanwhile, the present invention, by the method for blending and phase inversion, adds quaternary ammonium graphene oxide to modified polysulfone, is then coated and cast into film, effectively improves the hydrophilicity of modified polysulfone filter membrane, synergizes with amide groups, further improves the permeability of polypeptide molecule, improves the recovery rate of polypeptide.

Description

Technical Field

[0001] The present invention relates to the technical field of polypeptide preparation, and in particular to a method for preparing nonapeptide-1. Background Art

[0002] In the cosmetics field, nonapeptide-1, a beauty peptide, has attracted much attention for its remarkable effects in whitening, brightening, and removing freckles. Nonapeptide-1 inhibits the binding of melanocyte-stimulating hormone to the MCI-R receptor on melanocytes, thereby activating tyrosinase, further affecting the formation of melanin and reducing melanin production, thereby achieving the effects of brightening and even skin tone.

[0003] In the prior art, the synthesis of nonapeptide-1 is generally carried out using methods such as solid-phase peptide synthesis or liquid-phase peptide synthesis. These methods have been widely used in the field of peptide synthesis. However, the synthesis of nonapeptide-1 still faces many challenges, mainly manifested in the presence of various side reactions or incomplete removal of protective agents during the synthesis process, resulting in the presence of impurity peptides of various molecular weights in the crude synthesized nonapeptide-1, or incomplete removal of impurities such as protective agents, thus requiring purification. Commonly used peptide separation and purification techniques include reversed-phase high-performance liquid chromatography, ion exchange chromatography, gel permeation chromatography, ultrafiltration, and membrane separation. A single separation and purification technique is often difficult to isolate nonapeptide-1 to the desired purity, so multiple repeated separations or the simultaneous use of multiple separation and purification techniques are required. For example, patent CN106749526B provides a low-cost method for purifying nonapeptide-1, which uses reversed-phase high-performance liquid chromatography and weak anion exchange chromatography to purify nonapeptide-1, obtaining nonapeptide-1 with a purity greater than 99%. However, the yield of this method is only 79%.

[0004] In summary, it is urgent to develop a new technical solution to solve the problems existing in the existing technology.

[0005] The present invention provides a method for preparing nonapeptide-1. First, a crude nonapeptide-1 product is synthesized by a solid-phase synthesis method, and then purified by combining a modified polysulfone filter membrane, a reversed-phase polymer column, and a weak anion exchange column, thereby greatly improving the purification efficiency. The present invention controls the amount of the acylating agent so that the modified polysulfone filter membrane achieves a partially hydrophilic modification effect. While amide groups are grafted on the filter membrane surface and micropores, a large number of amino groups are retained, greatly enhancing the compatibility of the modified polysulfone filter membrane with polypeptides and the permeability of polypeptide molecules. The polypeptide molecules can be quickly and efficiently separated from impurities, thereby improving the recovery rate of the polypeptides. At the same time, the present invention adds quaternary ammonium graphene oxide to the modified polysulfone through a blending and phase conversion method, and then casts it into a membrane, effectively improving the hydrophilicity of the modified polysulfone filter membrane, synergistically acting with the amide groups of the modified polysulfone, further improving the permeability of the polypeptide molecules, and improving the recovery rate of the polypeptides.

[0006] One object of the present invention is to provide a method for preparing nonapeptide-1, which comprises the following steps:

[0007] S1. Preparation of modified polysulfone filter membrane, the preparation of the modified polysulfone filter membrane comprises the following steps:

[0008] L1. Adding graphene oxide to N,N-dimethylformamide, ultrasonically dispersing, then adding a tertiary amine modifier, stirring to react, purifying, and drying to obtain tertiary amine graphene oxide;

[0009] L2, adding the tertiary amine graphene oxide to ethanol, ultrasonically dispersing, then adding a quaternary ammonium modifier, heating for reaction, purifying, and drying to obtain quaternary ammonium graphene oxide;

[0010] L3, placing the polysulfone in a plasma treatment device, introducing nitrogen and hydrogen for plasma treatment to obtain amino polysulfone; blending the amino polysulfone with an acylating agent for reaction, purifying, and drying to obtain modified polysulfone;

[0011] L4, adding the modified polysulfone to a solvent, adding the quaternary ammonium graphene oxide, ultrasonicating, heating and stirring, and then casting into a membrane to obtain a modified polysulfone filter membrane;

[0012] S2, synthesizing the crude nonapeptide-1 by solid phase synthesis;

[0013] S3, adding the crude nonapeptide-1 to water, sonicating, and filtering with the modified polysulfone filter membrane to obtain a nonapeptide-1 mixture;

[0014] S4, purifying the nonapeptide-1 mixture by reverse-phase high performance liquid chromatography to obtain crude nonapeptide-1;

[0015] S5. Purifying the crude nonapeptide-1 by anion exchange chromatography to obtain highly pure nonapeptide-1.

[0016] Further, in step L1, the tertiary amine modifier is selected from one or more of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, triethylamine, N,N-dimethyl-1,3-propylenediamine, N,N-disalicylidenepropylenediamine, N,N'-dimethyl-1,4-butanediamine, 1,4-bis(dimethylamino)butane, N,N'-dihydroxy-2,3-dimethyl-2,3-butanediamine, N-hydroxysuccinimide, N-hydroxysulfosuccinimide, 4-dimethylaminopyridine, N-hydroxybenzotriazole, N,N-dicyclohexylcarbodiimide or 3-dimethylaminopropylamine.

[0017] Furthermore, in step L1, the molar ratio of the graphene oxide to the tertiary amine modifier is 1:(1-10).

[0018] Furthermore, in step L2, the quaternary ammonium modifier is selected from one or more of chlorobutane, chloropentane, hexyl chloride, chloroheptane, bromobutane, bromopentane, hexyl bromide, and bromoheptane.

[0019] Furthermore, in step L2, the molar ratio of the tertiary amine graphene oxide to the quaternary ammonium modifier is 1:(1-5).

[0020] Furthermore, in step L3, the plasma treatment conditions are: excitation by high-frequency and high-voltage discharge, with a frequency of 20-30 KHz and a power of 10-15 W.

[0021] Furthermore, in step L3, the volume ratio of nitrogen to hydrogen is 1:(2-5).

[0022] Furthermore, in step L3, the acylating agent is selected from one or more of valeryl chloride, hexanoyl chloride, heptanoyl chloride or octanoyl chloride.

[0023] Furthermore, in step L3, the molar ratio of the aminopolysulfone to the acylating agent is 1:(0.1-0.5).

[0024] Furthermore, in step L4, the mass ratio of the modified polysulfone to the quaternary ammonium graphene oxide is 100:(0.1-1).

[0025] Furthermore, in step L4, the solvent is selected from one or more of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide.

[0026] Furthermore, the preparation method of the crude nonapeptide-1 comprises the following steps:

[0027] P1, mixing the resin with dichloromethane, soaking and swelling, and purifying to obtain an activated resin;

[0028] P2, dissolving the first Fmoc-protected amino acid, HBTU, and DMAP in DMF, adding DIEA, mixing evenly, then adding to the activated resin, shaking for reaction, and purifying to obtain the resin coupled with the first amino acid;

[0029] P3, adding a mixed solution of acetic anhydride, pyridine and DMF to the resin coupled with the first amino acid, shaking the reaction to block the unreacted functional groups on the resin; then washing with DMF, DCM and DMF in sequence, adding a mixed solution of piperidine and DMF to deprotect the resin functional groups;

[0030] P4. Repeat steps P2-P3 to carry out the peptide grafting reaction, then remove the resin, purify and dry to obtain the crude product of nonapeptide-1.

[0031] The present invention has the following beneficial effects:

[0032] (1) In the purification process of nonapeptide-1, the present invention uses a modified polysulfone filter membrane, a reversed-phase polymer column and a weak anion exchange column in combination, thereby greatly improving the purification efficiency. The modified polysulfone filter membrane is obtained by aminating polysulfone, reacting with an acylating agent, and then blending with quaternary ammonium graphene oxide to form a cast membrane. By controlling the amount of the acylating agent, the present invention achieves a partially hydrophilic modification effect on the modified polysulfone filter membrane. While amide groups are grafted on the surface and micropores of the filter membrane, a large number of amino groups are retained. This greatly enhances the compatibility of the modified polysulfone filter membrane with the polypeptide, increases the filtration area, and enhances the permeability of the polypeptide molecules. The polypeptide molecules can be quickly and efficiently separated from impurities, thereby improving the recovery rate of the polypeptide.

[0033] (2) The quaternary ammonium graphene oxide of the present invention is obtained by reacting graphene oxide with a tertiary amine modifier and a quaternary ammonium modifier. Its surface and edges have a large number of quaternary ammonium salt groups and hydroxyl groups, and have good hydrophilicity. The present invention adds the quaternary ammonium graphene oxide to the modified polysulfone by a blending and phase conversion method, and then casts it into a membrane, effectively improving the hydrophilicity of the modified polysulfone filter membrane and significantly enhancing its permeability, adsorption and anti-fouling properties. It synergizes with the amide group of the modified polysulfone to further improve the permeability of polypeptide molecules and improve the recovery rate of polypeptides. DETAILED DESCRIPTION

[0034] In order to more clearly illustrate the technical solutions of the present invention, the following examples are given. Unless otherwise stated, the raw materials, reactions and post-processing methods mentioned in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0035] The terms "preferred," "preferably," "more preferred," and the like, used herein, refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

[0036] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties to be obtained by the present invention.

[0037] The following raw materials are used in the present invention:

[0038] Wang resin in the examples and comparative examples of the present invention was purchased from Jier Biochemical (Shanghai) Co., Ltd.

[0039] Fmoc-Val-OH in the examples and comparative examples of the present invention was purchased from Merck KGaA.

[0040] The polysulfones in the examples and comparative examples of the present invention were purchased from Hubei Kewode Chemical Co., Ltd.

[0041] The graphene oxide in the examples and comparative examples of the present invention was purchased from Anhui Kerun Nanotechnology Co., Ltd.

[0042] Example 1

[0043] A method for preparing nonapeptide-1, comprising the following steps:

[0044] S1. Preparation of modified polysulfone filter membrane, the preparation of the modified polysulfone filter membrane comprises the following steps:

[0045] L1. Add 0.2 g of graphene oxide to 100 g of N,N-dimethylformamide and ultrasonically disperse for 2 h. Then add 3 g of N,N-dicyclohexylcarbodiimide and 0.2 g of 4-dimethylaminopyridine and activate for 30 min. Then add 4.5 g of 3-dimethylaminopropylamine and react in a water bath at room temperature with stirring for 24 h. Centrifuge, wash, and dry to obtain tertiary amine graphene oxide.

[0046] L2, adding 0.1 g of the tertiary amine graphene oxide to 100 g of ethanol, ultrasonically dispersing for 30 min, then adding 5 g of bromobutane, stirring in a water bath at 70° C. for 12 h, centrifuging, washing, and drying to obtain quaternary ammonium graphene oxide;

[0047] L3. Place 5 g of polysulfone in a plasma treatment device, introduce nitrogen and hydrogen (volume ratio of 1:3, gas flow rate of 30 ml / min), and perform plasma treatment at a frequency of 20 kHz and a power of 15 W to obtain aminopolysulfone; blend the aminopolysulfone, 0.5 mL of triethanolamine, and 60 mL of dichloromethane, stir evenly, then place in an ice-water bath, add 0.5 mL of hexanoyl chloride, remove the ice-water bath after completion, stir at room temperature for 2 h, filter, wash, and dry to obtain modified polysulfone;

[0048] L4, adding the modified polysulfone to N-methylpyrrolidone, and then adding the quaternary ammonium graphene oxide (the mass ratio of modified polysulfone, N-methylpyrrolidone and quaternary ammonium graphene oxide m / m / m=100:1000:0.5), ultrasonicating for 20 min, stirring at 70°C for 12 h, cooling to room temperature, and then casting into a membrane to obtain a modified polysulfone filter membrane;

[0049] S2, synthesizing the crude nonapeptide-1 by solid phase synthesis;

[0050] S3, adding 0.5 g of the crude nonapeptide-1 to 10 mL of distilled water, dispersing by ultrasonication to completely dissolve it, and then filtering with a modified polysulfone filter membrane to obtain a nonapeptide-1 filtrate;

[0051] S4. Using high performance liquid chromatography, the nonapeptide-1 filtrate is crudely purified using a reverse phase polymer column to obtain crude nonapeptide-1. The purification conditions are as follows:

[0052] Column packing: F-type SBC MCI GEI reversed-phase chromatography packing (Chengdu Kepu Biotechnology) with a particle size of 30-50 μm; column filling volume: 30 mL;

[0053] Mobile phase A: 0.1 mol / L trifluoroacetic acid in water; Mobile phase B: 0.1 mol / L trifluoroacetic acid in methanol;

[0054] Flow rate: 4 mL / min; column temperature: 40°C; detection wavelength: 215 nm;

[0055] Gradient: 0-10 min: A:B from 70:30 to 55:45; 15-40 min: A:B from 55:45 to 40:60;

[0056] Before injection, the column was equilibrated with 0.1 mol / L trifluoroacetic acid aqueous solution, and then the sample was loaded and the target peak was collected. The solution was concentrated by rotary evaporation at 40°C under reduced pressure until the content of nonapeptide-1 was 50 mg / mL.

[0057] S5. The concentrated solution obtained in step S4 was subjected to a weak anion exchange column to remove trifluoroacetic acid to obtain highly purified nonapeptide-1 with a purity greater than 99% and a yield of 93%. The purification conditions were as follows:

[0058] Column packing: DEAE high-flow agarose microspheres with a particle size of 50-160 μm (Xi'an Jiaotong University Baosai Biotechnology); column filling volume: 30 mL;

[0059] Mobile phase: 2% acetic acid aqueous solution;

[0060] Flow rate: 4 mL / min; column temperature: 40°C; detection wavelength: 215 nm;

[0061] Before injection, the chromatographic column was equilibrated with an aqueous acetic acid solution having a volume concentration of 2%, and then the sample was loaded, and the target peak was collected, concentrated under reduced pressure, and freeze-dried.

[0062] The method for synthesizing the crude nonapeptide-1 in step S2 comprises the following steps:

[0063] A crude nonapeptide-1 product, wherein the amino acid sequence of the nonapeptide-1 is Met-Pro-D-Phe-Arg-D-Trp-Phe-Lys-Pro-Val.

[0064] The synthesis method of the above-mentioned crude nonapeptide-1 comprises the following steps:

[0065] P1, 1.5 g of Wang resin was mixed with 8.0 mL of anhydrous dichloromethane (DCM), soaked and swelled for 20 h, and the solvent DCM was removed under reduced pressure to obtain an activated resin;

[0066] P2, 0.15 mmol Fmoc-Val-OH, 0.15 mmol HBTU, and 15 mg DMAP were dissolved in 4.0 mL DMF, 0.15 mL DIEA was added, and then the mixture was added to the activated resin. The mixture was shaken at room temperature for 20 h, the solvent was blown dry with nitrogen, and then washed five times with 4.0 mL DMF to obtain the resin to which the first amino acid was attached;

[0067] P3, adding a mixed solution of acetic anhydride, pyridine and DMF (v / v / v = 2:1:3) to the resin connected to the first amino acid, and shaking for 30 minutes to obtain a resin with unreacted functional groups blocked; washing the resin with unreacted functional groups blocked with DMF, DCM and DMF three times, each for 5 minutes; then deprotecting with 20% pyridine-DMF solution twice, each for 20 minutes, to obtain a resin with deprotected functional groups;

[0068] P4. The resin with deprotected functional groups was washed three times with DMF, and then steps P2-P3 were repeated to connect the remaining amino acids in sequence to obtain a resin containing a polypeptide; the polypeptide-containing resin was washed three times with DMF, DCM, and DMF, respectively, and then vacuum-dried; then 5.0 mL of a mixed solution of trifluoroacetic acid, pure water, thioanisole, EDT, and phenol (v / v / v / v / v=82.5:5:5:2.5:5) was slowly added at room temperature, reacted for 4 h, filtered, and the solvent was blown dry with nitrogen until 1 / 10 volume of the solution remained. 5.0 mL of anhydrous ether was poured into the residual liquid, and a white flocculent precipitate appeared. The mixture was centrifuged at 5000 rpm for 10 min, the supernatant was removed, 5.0 mL of anhydrous ether was added to the precipitate, shaken, and centrifuged under the same conditions for 10 min, and repeated once. The precipitate was vacuum-dried for 24 h to obtain a crude product of nonapeptide-1.

[0069] Example 2

[0070] A method for preparing nonapeptide-1. This embodiment differs from Example 1 in that, in step L4, the mass ratio of the modified polysulfone to the quaternary ammonium graphene oxide is 100:0.3, and the amounts of other components and the preparation method are the same as in Example 1. This embodiment obtains high-purity nonapeptide-1 with a purity greater than 99% and a purification yield of 90%.

[0071] Example 3

[0072] A method for preparing nonapeptide-1 was described. This example differs from Example 1 in that 0.5 mL of valeryl chloride was added in step L3. The amounts of other components and the preparation method were the same as in Example 1. This example obtained highly pure nonapeptide-1 with a purity greater than 99% and a purification yield of 91%.

[0073] Comparative Example 1

[0074] A method for preparing nonapeptide-1 is disclosed. This comparative example differs from Example 1 in that steps L1 and L2 are omitted, and in step L4, the mass of quaternary ammonium graphene oxide is replaced with commercially available graphene oxide. The amounts of other components and the preparation method are the same as those in Example 1. This comparative example yields highly pure nonapeptide-1 with a purity greater than 99% and a purification yield of 78%.

[0075] Comparative Example 2

[0076] A method for preparing nonapeptide-1 is disclosed. This comparative example differs from Example 1 in that, in step L3, the polysulfone plasma treatment step is omitted, and the aminopolysulfone is replaced with polysulfone. The amounts of other components and the preparation method are the same as those in Example 1. This comparative example yields highly pure nonapeptide-1 with a purity greater than 99% and a purification yield of 73%.

[0077] Comparative Example 3

[0078] A method for preparing nonapeptide-1 is disclosed. This comparative example differs from Example 1 in that, in step L3, the acylation reaction is omitted, and the aminopolysulfone is used as a modified polysulfone for subsequent reactions. The amounts of other components and the preparation method are the same as those in Example 1. This comparative example yields highly pure nonapeptide-1 with a purity greater than 99% and a purification yield of 72%.

[0079] Comparative Example 4

[0080] A method for preparing nonapeptide-1 was described. This comparative example differed from Example 1 in that 5 mL of hexanoyl chloride was added in step L3. The amounts of other components and the preparation method were the same as in Example 1. This comparative example obtained highly pure nonapeptide-1 with a purity greater than 99% and a purification yield of 77%.

[0081] It can be seen from the above results that the present invention synthesizes the crude product of nonapeptide-1 by a solid phase synthesis method, and then purifies it by combining a modified polysulfone filter membrane, a reverse phase polymer column and a weak anion exchange column. The obtained high-purity nonapeptide-1 has a purity greater than 99% and a yield greater than 90%. Comparative Example 1 uses a modified polysulfone filter membrane prepared from commercially available graphene oxide, which has relatively poor hydrophilicity; Comparative Example 2 omits the polysulfone plasma treatment step and replaces the aminopolysulfone with polysulfone; Comparative Example 3 does not perform an acylation reaction, and uses the aminopolysulfone as a modified polysulfone for subsequent reactions. The prepared modified polysulfone filter membrane has poor compatibility with the polypeptide; Comparative Example 4 adds an excess of hexanoyl chloride, and the modified polysulfone filter membrane is more completely amidated, has fewer amino groups, and has poor hydrophilicity. Therefore, its purification yield for nonapeptide-1 is low, and the purification effect is not as good as the present invention.

[0082] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0083] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing nonapeptide-1, characterized in that: The preparation method of nonapeptide-1 comprises the following steps: S1. Preparation of modified polysulfone filter membrane, the preparation of the modified polysulfone filter membrane comprises the following steps: L1. Adding graphene oxide to N,N-dimethylformamide, ultrasonically dispersing, then adding a tertiary amine modifier, stirring to react, purifying, and drying to obtain tertiary amine graphene oxide; L2, adding the tertiary amine graphene oxide to ethanol, ultrasonically dispersing, then adding a quaternary ammonium modifier, heating for reaction, purifying, and drying to obtain quaternary ammonium graphene oxide; L3, placing the polysulfone in a plasma treatment device, introducing nitrogen and hydrogen for plasma treatment to obtain amino polysulfone; blending the amino polysulfone with an acylating agent for reaction, purifying, and drying to obtain modified polysulfone; L4, adding the modified polysulfone to a solvent, adding the quaternary ammonium graphene oxide, ultrasonicating, heating and stirring, and then casting into a membrane to obtain a modified polysulfone filter membrane; S2, synthesizing the crude nonapeptide-1 by solid phase synthesis; S3, adding the crude nonapeptide-1 to water, sonicating, and filtering with the modified polysulfone filter membrane to obtain a nonapeptide-1 mixture; S4, purifying the nonapeptide-1 mixture by reverse-phase high performance liquid chromatography to obtain crude nonapeptide-1; S5, purifying the crude nonapeptide-1 by anion exchange chromatography to obtain highly pure nonapeptide-1; in, In step L1, the tertiary amine modifier is N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and 3-dimethylaminopropylamine; In step L2, the quaternary ammonium modifier is bromobutyl; In step L3, the molar ratio of the aminopolysulfone to the acylating agent is 1:(0.1-0.5); The amino acid sequence of the nonapeptide-1 is Met-Pro-D-Phe-Arg-D-Trp-Phe-Lys-Pro-Val.

2. The method for preparing nonapeptide-1 according to claim 1, characterized in that: In step L1, the molar ratio of the graphene oxide to the tertiary amine modifier is 1:(1-10).

3. The method for preparing nonapeptide-1 according to claim 1, characterized in that: In step L2, the molar ratio of the tertiary amine graphene oxide to the quaternary ammonium modifier is 1:(1-5).

4. The method for preparing nonapeptide-1 according to claim 1, characterized in that: In step L3, the volume ratio of nitrogen to hydrogen is 1:(2-5).

5. The method for preparing nonapeptide-1 according to claim 1, characterized in that: In step L3, the acylating agent is selected from one or more of valeryl chloride, hexanoyl chloride, heptanoyl chloride or octanoyl chloride.

6. The method for preparing nonapeptide-1 according to claim 1, characterized in that: In step L4, the mass ratio of the modified polysulfone to the quaternary ammonium graphene oxide is 100:(0.1-1).

7. The method for preparing nonapeptide-1 according to claim 1, characterized in that: The preparation method of the crude nonapeptide-1 comprises the following steps: P1, mixing the resin with dichloromethane, soaking and swelling, and purifying to obtain an activated resin; P2, dissolving the first Fmoc-protected amino acid Val, HBTU, and DMAP in DMF, adding DIEA, mixing evenly, then adding to the activated resin, shaking the reaction, and purifying to obtain the resin coupled with the first amino acid Val; P3, adding a mixed solution of acetic anhydride, pyridine and DMF to the resin coupled with the first amino acid Val, shaking the reaction to block the unreacted functional groups on the resin; then washing with DMF, DCM and DMF in sequence, adding a mixed solution of piperidine and DMF to deprotect the resin functional groups; P4. Repeat steps P2-P3 to carry out the peptide grafting reaction, then remove the resin, purify and dry to obtain the crude product of nonapeptide-1.