Pig blood polypeptide with effect of relieving myelosuppression as well as preparation method and application of pig blood polypeptide

Abstract

The invention relates to the technical field of blood protein polypeptides, in particular to a pig blood polypeptide with an effect of relieving myelosuppression as well as a preparation method and application of the pig blood polypeptide. The preparation method of the pig blood polypeptide comprises the following steps: carrying out enzymolysis on a mixture of pig blood globulin powder and water at 50-60 DEG C under the action of enzyme for 2-8 hours, and carrying out enzyme deactivation treatment; the enzyme comprises at least one of alkaline protease, papain and neutral protease. According to the preparation method of the pig blood polypeptide, the spray-dried blood cells are used as a raw material to prepare the pig blood polypeptide, so that the dependence of a traditional process on fresh pig blood is broken through, and secondary high-value utilization of the spray-dried blood cells is realized; the pig blood polypeptide provided by the invention can be used for relieving the myelosuppression effect induced by 5-FU.

Description

Technical Field

[0001] This invention relates to the field of blood protein polypeptide technology, and in particular to a porcine blood polypeptide with the effect of relieving bone marrow suppression, its preparation method and application. Background Technology

[0002] Pig blood is one of the largest animal protein resources produced in the slaughtering industry, possessing enormous development potential. However, the comprehensive utilization rate of pig blood remains low at present. Only a small amount is used in traditional food processing, while a portion is processed into blood meal or fermented blood meal as feed additives, or used to extract heme, superoxide dismutase (SOD), and peptone, among other biochemical pharmaceutical products. A significant portion is discharged as waste, resulting in a tremendous waste of protein resources.

[0003] To enhance the utilization value of pig blood resources, modern biotechnology provides an effective way to convert pig blood proteins into bioactive small molecule peptides. Currently, the preparation of blood protein peptides mainly employs two process systems: enzymatic hydrolysis and fermentation, with fresh pig blood being the primary raw material. In actual production, the raw materials require multiple pretreatment processes, including anticoagulation and low-temperature refrigeration, which not only complicates the production process but also results in low utilization rates of the effective components of pig blood. Furthermore, pig blood protein peptide products reported in the literature are poorly soluble, with decreased solubility and increased turbidity at 50°C, affecting their bioavailability. Therefore, traditional processing methods and product quality severely restrict the industrial production and market application of pig blood protein peptide products.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide porcine blood polypeptides with the effect of alleviating bone marrow suppression, their preparation method, and applications. The preparation method of this invention uses hemoglobin powder as a raw material to prepare porcine blood polypeptides, breaking through the dependence of traditional processes on fresh porcine blood, simplifying pretreatment procedures, and realizing the secondary high-value utilization of hemoglobin powder, thus broadening the downstream applications of hemoglobin powder and extending the industrial chain. Furthermore, the porcine blood polypeptides prepared using the method of this invention have good quality and good solubility, and can alleviate 5-fluorouracil (5-FU)-induced bone marrow suppression.

[0006] To achieve the above-mentioned objective of the present invention, the first aspect of the present invention provides a method for preparing porcine blood polypeptide with the effect of relieving bone marrow suppression, comprising the following steps: enzymatic hydrolysis of a mixture of porcine blood globulin powder and water at 50-60°C for 2-8 hours under the action of an enzyme, followed by enzyme inactivation treatment; The enzyme includes at least one of alkaline protease, papain, and neutral protease.

[0007] In a specific embodiment of the present invention, the enzyme comprises alkaline protease and papain. Further, the enzyme comprises alkaline protease and papain in a mass ratio of 1:(0.1–5).

[0008] In a specific embodiment of the present invention, the amount of enzyme used is 0.5% to 8% of the mass of the porcine hemoglobin powder.

[0009] In a specific embodiment of the present invention, the mass ratio of the porcine hemoglobin powder to the water is 1:(5-30).

[0010] In a specific embodiment of the present invention, the enzyme inactivation treatment is performed by heating the enzyme. Further, the temperature for inactivating the enzyme is 95±5℃, and the time for inactivating the enzyme is 15±5 min.

[0011] In a specific embodiment of the present invention, after the enzyme inactivation treatment, the method further includes: filtering and collecting the filtrate. Further, the filtrate is concentrated, sterilized, and dried.

[0012] The second aspect of the present invention provides a porcine blood polypeptide with the effect of relieving bone marrow suppression, which is prepared by the method of the porcine blood polypeptide of the first aspect of the present invention.

[0013] In a specific embodiment of the present invention, the porcine blood polypeptide has a protein content ≥80wt% and a polypeptide content ≥70wt%. Further, the porcine blood polypeptide has an ash content ≤7.0wt%.

[0014] In a specific embodiment of the present invention, in the porcine blood polypeptide, peptides with a molecular weight less than 2000D account for ≥80wt% of all peptides.

[0015] The third aspect of the present invention provides the use of the porcine blood polypeptide of the second aspect of the present invention in the preparation of a formulation for alleviating 5-FU-induced myelosuppression.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the method for preparing pig blood polypeptide of the present invention, pig blood polypeptide is prepared by using hemoglobin powder as raw material, which breaks through the dependence of traditional process on fresh pig blood, simplifies the pretreatment process, realizes the secondary high-value utilization of hemoglobin powder, broadens the downstream application of hemoglobin powder, and extends the industrial chain. (2) The porcine blood polypeptide prepared by the method of the present invention has good quality, with a protein content of more than 80 wt%, a polypeptide content of more than 70 wt%, and peptides with a molecular weight of less than 2000D accounting for more than 80 wt% of all peptides; and the porcine blood polypeptide of the present invention has good solubility, with a transmittance of 68.16% at 620 nm at high temperature (50°C); (3) The porcine blood polypeptide of the present invention can be used to alleviate 5-FU-induced bone marrow suppression. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 The effect of porcine blood polypeptide provided in Example 10 of this invention on the proliferation of HS-5 cells; Figure 2 The effect of porcine blood polypeptide provided in Example 10 of the present invention on the proliferation of 5-FU-induced HS-5 cells at different doses; Figure 3 The effects of porcine blood polypeptides provided in different embodiments of the present invention on 5-FU-induced HS-5 cell proliferation.

[0019] In each figure, compared with the blank group, #p < 0.05, ##p < 0.01, ####p < 0.0001; compared with the model group, *p < 0.05, **p < 0.01, ****p < 0.0001. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0021] The first aspect of the present invention provides a method for preparing porcine blood polypeptide with the effect of relieving bone marrow suppression, comprising the following steps: enzymatic hydrolysis of a mixture of porcine blood globulin powder and water at 50-60°C for 2-8 hours under the action of an enzyme, followed by enzyme inactivation treatment; The enzyme includes at least one of alkaline protease, papain, and neutral protease.

[0022] This invention uses hemoglobin powder as a raw material to prepare porcine blood polypeptides. Combined with specific enzymatic hydrolysis, it improves the conversion of porcine blood protein into polypeptides, increases the yield of porcine blood polypeptides, and enhances both the protein and polypeptide content, thereby improving product quality. This invention's preparation method breaks through the dependence on fresh porcine blood in traditional processes and enables the secondary high-value utilization of hemoglobin powder, broadening its downstream applications and extending the industrial chain.

[0023] Furthermore, the preparation method of the present invention simplifies the pretreatment process and shortens the preparation cycle; and it eliminates the need to adjust pH, further reducing production costs.

[0024] The porcine hemoglobin powder of the present invention is porcine hemoglobin powder after porphyrin iron extraction.

[0025] In the different embodiments described below, the enzymatic hydrolysis temperature can be 50°C, 52°C, 55°C, 58°C, 60°C or any combination thereof, and the enzymatic hydrolysis time can be 2h, 4h, 6h, 8h or any combination thereof; the enzymatic hydrolysis temperature and time are controlled within the above ranges to balance the yield of porcine blood polypeptides, the protein content and polypeptide content in porcine blood polypeptides, and the production efficiency.

[0026] The enzymes used in this invention include at least one or at least two of alkaline protease, papain, and neutral protease, with alkaline protease and papain being preferred. Further, the enzymes comprise alkaline protease and papain in a mass ratio of 1:(0.1–5). In various embodiments, the mass ratio of alkaline protease to papain is within the range of 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, or any combination thereof. Regulating the type and ratio of enzymes within the above ranges further helps to improve the yield of porcine blood polypeptides and the protein and polypeptide content in porcine blood polypeptides, and ensures production efficiency.

[0027] In a specific embodiment of the present invention, the alkaline protease can be a conventional alkaline protease, and its enzyme activity can be 100,000 U to 300,000 U (e.g., 200,000 U), such as 100,000 U, 140,000 U, 180,000 U, 220,000 U, 260,000 U, 280,000 U, 300,000 U or any combination thereof; the papain can be a conventional papain, and its enzyme activity can be 600,000 U to 1,200,000 U (e.g., 800,000 U), such as 600,000 U, 700,000 U, 800,000 U, 900,000 U, 1,000,000 U, 1,100,000 U, 1,200,000 U or any combination thereof.

[0028] In a specific embodiment of the present invention, the amount of enzyme used is 0.5% to 8% of the mass of porcine hemoglobin powder, such as 0.5%, 1%, 2%, 4%, 5%, 6%, 8%, or any combination thereof.

[0029] In a specific embodiment of the present invention, the mass ratio of porcine hemoglobin powder to water is 1:(5-30), such as 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20, 1:22, 1:25, 1:28, 1:30, or any combination thereof.

[0030] In a specific embodiment of the present invention, the enzyme inactivation treatment is performed by heating the enzyme. Further, the temperature for enzyme inactivation is 95±5℃, and the time for inactivation is 15±5 min.

[0031] In a specific embodiment of the present invention, after enzyme inactivation treatment, the process further includes: filtering and collecting the filtrate. Further, the filtrate is concentrated, sterilized, and dried.

[0032] In specific embodiments of the present invention, the filtration methods include, but are not limited to, plate and frame filtration, ceramic membrane filtration, etc.

[0033] In a specific embodiment of the present invention, the concentration conditions include: concentrating to a Baumé degree of 10-15 under vacuum conditions at 55-65°C. The vacuum degree is 0.005-0.009 MPa.

[0034] In a specific embodiment of the present invention, sterilization is performed by steam sterilization. Further, instantaneous sterilization is carried out using saturated steam at 130–140°C.

[0035] In a specific embodiment of the present invention, the drying is spray drying. Specifically, a centrifugal spray dryer can be used for spray drying. Further, the spray drying conditions include: inlet air temperature of 180–200°C, outlet air temperature of 80–100°C, nozzle rotation speed of 20–30 Hz, and a Mono pump operating at 60–90 V. The degree of filtrate concentration can be adjusted adaptively according to the material requirements of spray drying.

[0036] The second aspect of the present invention provides a porcine blood polypeptide with the effect of relieving bone marrow suppression, which is prepared by the method of the porcine blood polypeptide of the first aspect of the present invention.

[0037] In a specific embodiment of the present invention, the porcine blood polypeptide contains ≥80wt% protein and ≥70wt% polypeptide. Further, the porcine blood polypeptide contains ≤7.0wt% ash.

[0038] In different embodiments, the protein content in the porcine blood polypeptide can be a range of 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, or any two of these; the polypeptide content can be a range of 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%, 76wt%, 77wt%, 78wt%, 79wt%, 80wt%, or any two of these.

[0039] In a specific embodiment of the present invention, in the porcine blood polypeptide, peptides with a molecular weight less than 2000D account for ≥80wt% of all peptides.

[0040] In different embodiments, the content of peptides with a molecular weight less than 2000D can be within the range of 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, or any combination thereof, of all peptides.

[0041] The third aspect of the present invention provides its use in the preparation of porcine blood polypeptides of the second aspect of the present invention for use in formulations to alleviate 5-FU-induced myelosuppression.

[0042] Chemotherapy, as one of the treatments for malignant tumors, is widely used in clinical medicine. 5-FU, a first-line chemotherapy drug widely used in the treatment of colon cancer, liver cancer, colorectal cancer, and breast cancer, is converted into 5-fluorouracil deoxynucleotides within tumor cells after entering the body. This inhibits deoxythymidine synthase, inhibits the methylation of deoxyuridine to deoxythymidine, and affects DNA synthesis. Simultaneously, 5-FU also interferes with RNA synthesis, inhibiting tumor cell proliferation and thus exerting its anti-tumor effect. It is worth noting that anti-tumor drugs are not highly selective, often inadvertently damaging cells with high proliferative capacity and high DNA content in certain normal tissues, such as bone marrow, hair follicle epithelium, and gastrointestinal epithelial cells. Therefore, 5-FU also has significant adverse reactions such as bone marrow suppression, peripheral blood cell reduction, and gastrointestinal reactions. The porcine blood polypeptide prepared in this invention can alleviate the bone marrow suppression induced by 5-FU.

[0043] The following specific implementation may use some raw material information, but is not limited to: Porcine blood cell protein powder: protein ≥75%, ash ≤5%, moisture ≤8.0%, volatile basic nitrogen ≤35mg / 100g, heavy metals ≤2mg / kg; Porcine whole blood protein powder: protein ≥70%, ash ≤8%, moisture ≤8.0%, volatile basic nitrogen ≤35mg / 100g; Alkaline protease: 200,000 U, commercially available; Papain: 800,000 U, commercially available; Neutral protease: 150,000 U, commercially available.

[0044] Example 1 This embodiment provides a method for preparing porcine blood polypeptides, including the following steps: (1) Take porcine hemoglobin powder and water at a mass ratio of 1:5, stir and mix evenly, heat to 55℃, add 0.5wt% of enzyme based on the mass of porcine hemoglobin powder, and enzymatically hydrolyze at 55℃ for 2 hours. Then heat to 90℃ and inactivate the enzyme for 15 minutes. The enzymes are alkaline protease and papain at a mass ratio of 1:0.1.

[0045] (2) The material after enzyme inactivation treatment in step (1) is filtered by plate and frame filtration, the filtrate is collected and concentrated under vacuum at 60°C and 0.007 MPa until the Baume degree is 12; then it is instantaneously sterilized by saturated steam at 135°C; and spray dried by centrifugal spray dryer to obtain porcine blood polypeptide; wherein the spray drying conditions include: inlet air temperature 190°C, outlet air temperature 90°C, nozzle speed 25Hz, and Mono pump 75V.

[0046] Examples 2-21 Examples 2 to 21 are prepared in accordance with the preparation method of Example 1, with the following differences: at least one of the following in step (1) is different: the ratio of porcine hemoglobin powder to water, the type of enzyme, the amount of enzyme used (the amount of enzyme used in the table below refers to the proportion of the added enzyme to the mass of porcine hemoglobin powder), and the enzymatic hydrolysis time. The specific differences are shown in Table 1.

[0047] Table 1. Relevant information for different embodiments

[0048] Comparative Example 1 Comparative Example 1 uses the same preparation method as Example 10, except that the raw materials in step (1) are different. The specific differences are as follows, and the rest are the same as in Example 10.

[0049] In Comparative Example 1, an equal weight of porcine whole blood protein powder was used to replace the porcine blood cell protein powder in Example 10.

[0050] Experimental Example 1 To compare and illustrate the physicochemical properties of the porcine blood polypeptides prepared in various embodiments and comparative examples of the present invention, the following tests were conducted, and the specific test results are shown in Table 2. The methods for determining the protein content, polypeptide content, and proportion of peptides with a molecular weight less than 2000D were respectively carried out in accordance with the corresponding detection methods in GB / T22492-2008 "Soybean Peptide Powder".

[0051] Table 2 Physicochemical properties of different porcine blood polypeptides, etc.

[0052] Based on the test results in Table 2, comparing the results of the comparative examples with those of Comparative Example 1, it can be seen that when using hemoglobin powder as raw material to prepare porcine blood polypeptides, combined with appropriate enzymatic hydrolysis, the yield of porcine blood polypeptides can be significantly improved, and the protein content in the porcine blood polypeptides can be increased, compared to the method used in Comparative Example 1, which used whole porcine blood protein powder as raw material. Comparing Examples 10 with Examples 18-21, it can be seen that when alkaline protease and papain are combined in a certain proportion, the yield of the obtained porcine blood polypeptides is significantly better than that obtained with other enzymes, and the protein content is also improved to a certain extent.

[0053] Transmittance was measured in examples and comparative examples with protein content ≥80%, peptide content ≥70%, and yield ≥60%, and the results are shown in Table 3. The test method included: mixing porcine blood peptides with distilled water in a specific ratio to prepare a 5% (w / w) solution; using spectrophotometry, with distilled water as a blank, and under high temperature (50℃) conditions, measuring the transmittance T value at 620 nm. Higher transmittance indicates better product clarity.

[0054] Table 3 Transmittance of different porcine blood polypeptides

[0055] As can be seen from the test results above, the light transmittance of the products in the examples is better than that of the comparative examples, with Example 10 having the best light transmittance.

[0056] Experimental Example 2 Effects of porcine blood peptides on 5-FU-induced proliferation of HS-5 cells 1. Effects of different concentrations of porcine blood polypeptide (Example 10) on the proliferation of HS-5 cells Adjust the HS-5 cell concentration to 1×10⁻⁶. 6 / mL inoculated at 25cm 2 In culture flasks, DEME high-glucose medium containing 10% FBS was incubated at 37°C in a 5% CO2 incubator. Once cell confluence reached over 80%, cells were passaged using 0.25% trypsin and selected for the logarithmic growth phase for subsequent experiments. The cultured HS-5 cells were randomly divided into different dosage groups, and porcine blood polypeptide from Example 10 was added to achieve final concentrations of 200 μg / mL, 400 μg / mL, 800 μg / mL, 1600 μg / mL, 3200 μg / mL, and 6400 μg / mL, respectively. Cells were cultured for 48 hours, and HS-5 cell viability was measured using the CCK-8 assay. The test results are shown below. Figure 1 .from Figure 1The results showed that within the concentration range of 200–6400 μg / mL, the proliferation rate of HS-5 cells was >80%, indicating that porcine blood polypeptide had no significant cytotoxicity to HS-5 cells within this range. Furthermore, within the concentration range of 200–800 μg / mL, the proliferation rate of HS-5 cells was positively correlated with the concentration of porcine blood polypeptide. Subsequent studies selected 400 μg / mL, 800 μg / mL, and 1600 μg / mL as the effective concentrations for the low-dose, medium-dose, and high-dose groups, respectively.

[0057] 2. Porcine blood polypeptide alleviates 5-FU-induced inhibition of HS-5 cell proliferation. Take cells in the logarithmic growth phase, according to 1×10 4 HS-5 cells were seeded in 96-well plates and cultured at 37°C with 5% CO2 for 24 h. The cultured HS-5 cells were then randomly divided into three groups: a blank control group, a model group, and a dose group. The blank control group was cultured in standard medium for 48 h; the model group was treated with standard medium plus 25 μg / mL 5-FU for 48 h; and the dose groups were pretreated with standard medium plus 25 μg / mL 5-FU for 6 h, followed by the addition of porcine blood polypeptide from Example 10 at final concentrations of 400 μg / mL, 800 μg / mL, and 1600 μg / mL (low-dose group (PBP-L), medium-dose group (PBP-M), and high-dose group (PBP-H)), and cultured for 48 h. HS-5 cell viability was measured using the CCK-8 assay. The results are shown below. Figure 2 .from Figure 2 The results showed that the proliferation rate of HS-5 cells in the model group was significantly lower than that in the control group, and the difference was highly significant, indicating that 5-FU had a significant inhibitory effect on HS-5 cells, thus the HS-5 cell myelosuppression model was successfully established. The proliferation rate of HS-5 cells in all dose groups of porcine blood polypeptide was higher than that in the model group, and the differences were highly significant, with the highest cell proliferation rate (94.1%) in the medium-dose group. This indicates that porcine blood polypeptide can significantly improve the inhibitory effect of 5-FU on the proliferation of HS-5 cells.

[0058] 3. Effects of different embodiments and raw materials on 5-FU-induced proliferation of HS-5 cells Take cells in the logarithmic growth phase, according to 1×10 4HS-5 cells were seeded in 96-well plates and cultured at 37°C with 5% CO2 for 24 hours. The cultured HS-5 cells were randomly divided into a blank group, a model group, Example 10 group, Example 1 group, Example 17 group, and a raw material group. Blank group: cultured in conventional culture medium for 48 hours; Model group: cultured in conventional culture medium with a final concentration of 25 μg / mL 5-FU for 48 hours; Example 10 group: pretreated with conventional culture medium with a final concentration of 25 μg / mL 5-FU for 6 hours, then added with a final concentration of 800 μg / mL porcine blood polypeptide from Example 10, and co-cultured for 48 hours; Example 1, Example 17, and the raw material group were cultured according to the method described in Example 10, except that they were respectively supplemented with a final concentration of 800 μg / mL porcine blood polypeptide from Examples 1 and 17, and porcine blood globulin powder. HS-5 cell viability was determined using the CCK-8 assay. The test results are shown below. Figure 3 .from Figure 3 As can be seen, the proliferation rate of HS-5 cells in the model group was significantly lower than that in the blank group, and the difference was extremely significant, indicating that 5-FU had a significant inhibitory effect on HS-5 cells, meaning that the HS-5 cell bone marrow suppression model was successfully established. After intervention with Example 1, Example 10, Example 17, and porcine hemoglobin powder, the proliferation activity of HS-5 cells significantly increased, and the differences compared with the model group were extremely significant. Among them, Example 10 showed the best effect in alleviating the inhibitory effect of 5-FU on HS-5 cell activity, and the difference compared with the model group was extremely significant.

[0059] In summary, the porcine blood polypeptide of the present invention, when at a concentration range of 400–1600 μg / mL, has no cytotoxicity to HS-5 cells and can significantly alleviate the inhibitory effect of 5-FU on the proliferation of HS-5 cells, that is, it has the effect of alleviating bone marrow suppression.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing porcine blood polypeptides with the effect of alleviating bone marrow suppression, characterized in that, The process includes the following steps: a mixture of porcine hemoglobin powder and water is enzymatically hydrolyzed at 50–60°C for 2–8 hours under the action of enzymes, followed by enzyme inactivation treatment; The enzyme includes at least one of alkaline protease, papain, and neutral protease.

2. The preparation method according to claim 1, characterized in that, The enzymes include alkaline protease and papain; Preferably, the enzyme comprises an alkaline protease and a papain in a mass ratio of 1:(0.1-5).

3. The preparation method according to claim 1, characterized in that, The amount of enzyme used is 0.5% to 8% of the mass of the porcine hemoglobin powder.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the porcine hemoglobin powder to the water is 1:(5-30).

5. The preparation method according to claim 1, characterized in that, The enzyme inactivation treatment is performed by heating to inactivate the enzyme. Preferably, the temperature for inactivating the enzyme is 95±5℃, and the time for inactivating the enzyme is 15±5min.

6. The preparation method according to claim 1, characterized in that, After the enzyme inactivation treatment, the method further includes: filtering and collecting the filtrate; Preferably, the filtrate is concentrated, sterilized, and dried.

7. A porcine blood polypeptide with the effect of alleviating bone marrow suppression, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. The porcine blood polypeptide according to claim 7, characterized in that, The porcine blood polypeptide contains ≥80wt% protein and ≥70wt% polypeptide. Preferably, the ash content of the porcine blood polypeptide is ≤7.0wt%.

9. The porcine blood polypeptide according to claim 7, characterized in that, In the porcine blood polypeptide, peptides with a molecular weight less than 2000D account for ≥80wt% of all peptides.

10. The use of the porcine blood polypeptide according to any one of claims 7 to 9 in the preparation of an agent for relieving 5-FU-induced myelosuppression.

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