A Thamnaconus modestus swim bladder antihypertensive peptide, its preparation method and application

Abstract

The present invention discloses a leatherjacket swim bladder antihypertensive peptide with angiotensin-converting enzyme (ACE) inhibitory activity, its preparation method and uses. The amino acid sequence of the antihypertensive peptide is Ser-Pro-Gly-Phe-Met (SPGFM), and the molecular weight detected by ESI / MS is 537.6 Da. The leatherjacket swim bladder of the present invention is pretreated by microwave and ultrasound, enzymolyzed, ultrafiltered, purified by gel chromatography and purified by reversed-phase high performance liquid chromatography (RP-HPLC) to obtain the antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM). The active peptide Ser-Pro-Gly-Phe-Met (SPGFM) prepared by the present invention has significant angiotensin-converting enzyme (ACE) inhibitory activity and protective effect on human umbilical vein endothelial cells (HUVEC), and can be used in drugs related to the treatment of hypertension.

Description

Technical Field

[0001] The present invention belongs to the technical field of bioengineering, and particularly relates to a leatherjacket swim bladder antihypertensive peptide, a preparation method thereof, and an application thereof. Background Art

[0002] Hypertension refers to a clinical syndrome in which the arterial systolic blood pressure and / or diastolic blood pressure increase (≥140 / 90 mmHg) at rest, and it may be accompanied by functional or organic damage to organs such as the heart, brain, and kidneys. Hypertension is a common and frequently-occurring disease. Generally, the onset of this disease is slow. Patients often have no symptoms in the early stage, or only have symptoms such as dizziness, headache, palpitation, and tinnitus. On the surface, it seems to be an independent disease, but in fact, it is the "culprit" leading to various serious complications such as stroke, hypertensive heart disease, and renal failure.

[0003] Angiotensin-I-Converting Enzyme (ACE) is a key enzyme in the angiotensin system. It can catalyze the conversion of angiotensin I into angiotensin II with a strong vasoconstrictive effect, and inactivate bradykinin with a blood pressure-lowering effect. Therefore, hypertension can be treated by inhibiting ACE activity. Angiotensin-converting enzyme inhibitors (ACEIs) have been widely studied for the prevention and control of hypertension. However, synthetic ACEIs have adverse side effects, such as persistent dry cough, rash, and taste disorders. Summary of the Invention

[0004] Based on this, this research topic uses leatherjacket swim bladder as the raw material and utilizes enzyme engineering technology to prepare an antihypertensive pentapeptide Ser-Pro-Gly-Phe-Met (SPGFM), which shows a significant antihypertensive effect and can be used as a drug or an adjuvant drug for the treatment of hypertension.

[0005] The first technical problem to be solved by the present invention is to provide a leatherjacket swim bladder antihypertensive pentapeptide aiming at the above technical status. This pentapeptide has a significant inhibitory effect on angiotensin-converting enzyme (ACE) and a significant protective effect on human umbilical vein endothelial cells (HUVEC).

[0006] The second technical problem to be solved by the present invention is to provide a preparation method of a leatherjacket swim bladder antihypertensive pentapeptide with ACE inhibitory effect.

[0007] The third technical problem to be solved by the present invention is to provide an application of a leatherjacket swim bladder antihypertensive pentapeptide with ACE inhibitory activity in the preparation of drugs or health products for the treatment of hypertension.

[0008] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is as follows: A Thamnaconus modestus swim bladder antihypertensive pentapeptide, the amino acid sequence of the antihypertensive pentapeptide is Ser-Pro-Gly-Phe-Met (SPGFM), and the molecular weight measured by ESI-MS is 537.6 Da.

[0009] The technical solution adopted by the present invention to solve the above-mentioned second technical problem is as follows: A preparation method of Thamnaconus modestus swim bladder antihypertensive peptide, which is characterized by including the following steps:

[0010] 1) Pretreatment of Thamnaconus modestus swim bladder: Thaw the Thamnaconus modestus swim bladder, remove impurities, homogenize it into a paste in a tissue homogenizer, then add it to a NaOH solution and soak at 4 °C for 9-12 h, filter, rinse the NaOH with distilled water, dry it, add ethyl acetate, and perform ultrasonic treatment at room temperature of 42 KHZ and 300 W for 15-20 min, centrifuge to remove the supernatant to obtain Thamnaconus modestus swim bladder powder;

[0011] 2) Preparation of Thamnaconus modestus swim bladder enzyme hydrolysate: Add the above-mentioned Thamnaconus modestus swim bladder powder to a glycine-NaOH buffer solution and mix, adjust the pH value of the mixed solution to 6.5-7.5, adjust the temperature to 45-55 °C, add neutral protease (5.0×10 4 U / g), and enzymatically hydrolyze for 3-5 h; after placing the enzyme hydrolysate in boiling water for 5-10 min, inactivate the enzyme activity; adjust the pH value of the mixed solution to 9.5-10.5, adjust the temperature to 40-45 °C, add alkaline protease (5.0×10 4 U / g), and enzymatically hydrolyze for 3-5 h; after placing the enzyme hydrolysate in boiling water for 5-10 min, inactivate the enzyme activity; obtain Thamnaconus modestus swim bladder enzyme hydrolysate;

[0012] 3) Ultrafiltration fractionation of Thamnaconus modestus swim bladder enzyme hydrolysate: Ultrafilter the Thamnaconus modestus swim bladder enzyme hydrolysate with 1 kDa, 5 kDa, and 10 kDa ultrafiltration membranes, respectively collect the components with molecular weights less than 1 kDa, 1-5 kDa, 5-10 kDa, and greater than 10 kDa, measure the angiotensin-converting enzyme (ACE) inhibitory activity of each component, and the component with the highest ACE inhibitory activity is the ultrafiltered enzyme hydrolysate, which is freeze-dried to obtain the ultrafiltered enzyme hydrolysate.

[0013] 4) Preparation of Thamnaconus modestus swim bladder antihypertensive peptide: Purify the ultrafiltered enzyme hydrolysate by column chromatography on Sephadex LH-20 and reverse-phase high-performance liquid chromatography (RP-HPLC) to obtain Thamnaconus modestus swim bladder antihypertensive peptide.

[0014] In some embodiments of the present invention, the Thamnaconus modestus in step 1) is Thamnaconus modestus.

[0015] In some embodiments of the present invention, in step 1), the concentration of the NaOH solution is 0.05 mol / L, and the weight-to-volume ratio of the filefish swim bladder to the NaOH solution is 1 g: 10 - 15 mL.

[0016] In some embodiments of the present invention, in step 1), the weight-to-volume ratio of the filefish swim bladder to ethyl acetate is 1 g: 8 - 10 mL.

[0017] In some embodiments of the present invention, in step 2), the concentration of the glycine-NaOH buffer solution is 0.05 mol / L and the pH is 9.5; in step 2), the weight-to-volume ratio of the filefish swim bladder powder to the glycine-NaOH buffer solution is 1 g: 6 - 8 mL.

[0018] In some embodiments of the present invention, in step 3), the addition amount of neutral protease is 1.0 - 2.0% of the mass of the filefish swim bladder powder.

[0019] In some embodiments of the present invention, in step 3), the addition amount of alkaline protease is 1.0 - 2.0% of the mass of the filefish swim bladder powder.

[0020] In some experimental embodiments of the present invention, the Sephadex LH-20 chromatography purification and RP-HPLC purification in step 4) are as follows:

[0021] Sephadex LH-20 chromatography purification: The ultrafiltered enzymatic hydrolysate is prepared into a solution of 45 - 55 μg / mL, separated by Sephadex LH-20 column chromatography, eluted with double-distilled water, and the elution fractions are collected according to the absorbance curve at 214 nm. Among them, the peak with the highest ACE inhibitory activity is the gel chromatography enzymatic hydrolysate, which is freeze-dried.

[0022] RP-HPLC purification: The above-mentioned filefish swim bladder gel chromatography enzymatic hydrolysate is prepared into a solution of 90 - 100 μg / mL with double-distilled water, purified by RP-HPLC, and 1 highly active oligopeptide Ser-Pro-Gly-Phe-Met (SPGFM) is obtained according to the ACE inhibitory activity of the prepared oligopeptide, and the molecular weight is determined by ESI-MS to be 537.6 Da.

[0023] Furthermore, the RP-HPLC conditions are as follows: the injection volume is 180 - 200 μL; the chromatographic column is Hypersil 300A C18 (250 mm × 10.0 mm, 10 μm); the mobile phase is 60% acetonitrile; the elution speed is 1.5 - 2.0 mL / min; the ultraviolet detection wavelength is 214 nm.

[0024] The technical solution adopted by the present invention to solve the above-mentioned third technical problem is as follows: an application of a Thamnaconus modestus swim bladder antihypertensive peptide. The Thamnaconus modestus swim bladder antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) of the present invention has a significant inhibitory effect on ACE, and the half inhibitory concentration (IC 50 ) is 25.78 ± 1.36 μM; in addition, Ser-Pro-Gly-Phe-Met (SPGFM) has no obvious toxicity to human umbilical vein endothelial cells (HUVEC), and can promote the release of the endogenous vasodilator nitric oxide (NO) in HUVEC cells and inhibit the generation of the endogenous vasoconstrictor endothelin-1 (ET-1). The Ser-Pro-Gly-Phe-Met (SPGFM) of the present invention has a certain antihypertensive and regulatory function on HUVEC cells, and can be applied to the field of preparing drugs or health foods related to the treatment of hypertension.

[0025] The present invention adopts a controllable and environmentally friendly bioenzymatic method, which can easily monitor the enzymatic hydrolysis process to maximize the release of the Thamnaconus modestus swim bladder antihypertensive peptide and improve the utilization rate of raw materials. The antihypertensive peptide prepared by the present invention is obtained by enzymatic hydrolysis of the Thamnaconus modestus swim bladder, which is safe, non-toxic and has significant ACE inhibitory activity, and has an antihypertensive effect on hypertensive patients.

[0026] The prepared SPGFM of the present invention can be used as a drug or health food. The process of the present invention is scientific and reasonable, simple to operate, and has strong industrial feasibility. Compared with the existing preparation methods, the present invention combines multiple means such as microwave and ultrasonic pretreatment of raw materials, neutral protease enzymatic hydrolysis, ultrafiltration, gel chromatography and RP-HPLC, with perfect technology, and the obtained antihypertensive peptide has high activity. Description of the Drawings

[0027] Figure 1 shows the inhibition rate (%) of angiotensin converting enzyme (ACE) by the enzymatic hydrolysate of Thamnaconus modestus swim bladder (TMPH) and its ultrafiltration fractionation components (TMPH-I to TMPH-IV) at a concentration of 5 mg / mL in the examples of the present invention.

[0028] Figure 2 is the chromatogram obtained when separating and purifying TMPH-I with a Sephadex LH-20 column (2.6 cm × 120 cm) in the examples of the present invention.

[0029] Figure 3 shows the inhibition rate (%) of angiotensin converting enzyme (ACE) by the ultrafiltration enzymatic hydrolysate of Thamnaconus modestus swim bladder (STH1) and its gel chromatography separation components (STH1A to STH1D) at a concentration of 5 mg / mL in the examples of the present invention.

[0030] Figure 4 This is a chromatogram obtained when a Hypersil 300A C18 (250 mm×10.0 mm, 10 μm) column is used to separate and purify TMPH-IC in an embodiment of the present invention.

[0031] Figure 5 The half inhibition rate (IC) of ACE by the components prepared by RP-HPLC in the present invention is 50 ).

[0032] Figure 6 It is a structural diagram of the puffer fish maw antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) according to an embodiment of the present invention.

[0033] Figure 7 It is a mass spectrum of the puffer fish maw antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) according to an embodiment of the present invention.

[0034] Figure 8 The present invention relates to the effect of the puffer fish maw antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) on the activity of human umbilical vein endothelial cells (HUVEC).

[0035] Figure 9 The present invention relates to the effect of the puffer fish maw antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) on the nitric oxide (NO) content in human umbilical vein endothelial cells (HUVEC).

[0036] Figure 10 The present invention relates to the effect of the puffer fish maw antihypertensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) on the content of endothelin-1 (ET-1) in human umbilical vein endothelial cells (HUVEC). DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The solvent used in the present invention is not particularly limited, and commercially available conventional solvents can be used.

[0038] Normal group: human umbilical vein endothelial cells (HUVEC) grown in culture medium without any treatment.

[0039] CP group: human umbilical vein endothelial cells (HUVEC) treated with the positive control drug captopril.

[0040] NE group: human umbilical vein endothelial cells (HUVEC) treated with the negative control drug norepinephrine.

[0041] SPGFM group: human umbilical vein endothelial cells (HUVEC) treated with oligopeptide SPGFM.

[0042] Example

[0043] A preparation method of Thamnaconus modestus swim bladder antihypertensive peptide, the preparation process is as follows: Thamnaconus modestus swim bladder → tissue disruption → microwave and ultrasonic pretreatment → enzymatic hydrolysis → ultrafiltration → gel chromatography purification → RP-HPLC purification → Thamnaconus modestus swim bladder antihypertensive peptide.

[0044] 1) Pretreatment of Thamnaconus modestus swim bladder: Thaw the Thamnaconus modestus swim bladder, remove impurities, homogenize it into a paste in a tissue homogenizer, then add it to a NaOH solution (0.05 mol / L) at a solid-liquid ratio of 1 g:13 mL and soak it at 4 °C for 11 h, filter, rinse the NaOH with distilled water, and dry. Add ethyl acetate at a ratio of 1 g:9 mL, and perform ultrasonic treatment at room temperature at 42 KHZ and 300 W for 19 min, centrifuge to remove the supernatant to obtain Thamnaconus modestus swim bladder powder.

[0045] 2) Preparation of Thamnaconus modestus swim bladder enzymatic hydrolysate: Mix the above Thamnaconus modestus swim bladder powder with 0.05 mol / L, pH 9.5 glycine-NaOH buffer at a weight-to-volume ratio of 1 g:8 mL, adjust the pH value of the mixture to 7.2, adjust the temperature to 48 °C, and add neutral protease (5.0×10 4 U / g) according to 1.2% of the mass of Thamnaconus modestus swim bladder powder, and perform enzymatic hydrolysis for 5 h; after placing the enzymatic hydrolysate in boiling water for 10 min, inactivate the enzyme activity; adjust the pH value of the mixture to 10, adjust the temperature to 45 °C, and add alkaline protease (5.0×10 4 U / g) according to 1.2% of the mass of Thamnaconus modestus swim bladder powder, and perform enzymatic hydrolysis for 3.5 h; after placing the enzymatic hydrolysate in boiling water for 8 min, inactivate the enzyme activity; obtain Thamnaconus modestus swim bladder enzymatic hydrolysate (TMPH).

[0046] 3) Ultrafiltration fractionation of Thamnaconus modestus swim bladder enzymatic hydrolysate: Ultrafilter the Thamnaconus modestus swim bladder enzymatic hydrolysate (TMPH) with 1 kDa, 5 kDa and 10 kDa ultrafiltration membranes to obtain 4 fractions, namely TMPH-I (MW < 1 kDa), TMPH-II (1 < MW < 5 kDa), TMPH-III (5 < MW < 10 kDa), TMPH-IV (MW ≥ 10 kDa) fractions. Refer to the literature [Tang Haixia, Wang Shuangshuang, Hao Guo, Song Yuxuan, Zhang Lei, Ge Wupeng. Structural identification and molecular binding mechanism analysis of a novel ovine casein ACE inhibitory peptide [J]. Food Industry Science, 43(1): 110-118], measure the angiotensin-converting enzyme (ACE) inhibitory activity of each fraction (see Figure 1 ), and the fraction TMPH-I with the highest ACE inhibitory activity is the ultrafiltered enzymatic hydrolysate, which is freeze-dried to obtain the ultrafiltered enzymatic hydrolysate.

[0047] 4) Preparation of the hypotensive peptide from the swim bladder of Thamnaconus septentrionalis: The ultrafiltration hydrolysate (TMPH-I) was successively purified by Sephadex LH-20 column chromatography and reverse-phase high performance liquid chromatography (RP-HPLC) to obtain the hypotensive peptide from the swim bladder of Thamnaconus septentrionalis.

[0048] ① Chromatographic purification with Sephadex LH-20: The ultrafiltration hydrolysate was prepared into a 50 μg / mL solution, separated by Sephadex LH-20 column chromatography, eluted with double-distilled water, and the elution fractions (TMPH-IA - TMPH-ID) were collected according to the absorbance curve at 214 nm (see Figure 2 ), and the angiotensin-converting enzyme (ACE) inhibitory activities of the fractions TMPH-IA - TMPH-ID were determined (see Figure 3 ). Among them, TMPH-IC had the highest ACE inhibitory activity and was the enzymatic hydrolysate of gel chromatography.

[0049] ② RP-HPLC purification: The enzymatic hydrolysate of gel chromatography (TMPH-IC) was prepared into a 95 μg / mL solution and purified by RP-HPLC (conditions: injection volume 180 μL; chromatographic column Hypersil 300A C18 (250 mm × 10.0 mm, 10 μm); mobile phase: 60% acetonitrile; elution rate 2.0 mL / min; UV detection wavelength 214 nm) (see Figure 4 ), and the half inhibitory concentration (IC 50 ) of angiotensin-converting enzyme (ACE) of each separated fraction (TMHP1 - TMHP5) was determined (see Figure 5 ). TMHP3 had the lowest ACE half inhibitory concentration (IC 50 ), and its amino acid sequence and molecular weight were determined.

[0050] ③ Structure detection: The fraction (TMHP3) with the lowest ACE half inhibitory concentration (IC 50 ) was collected, and the amino acid sequence was determined to be Ser-Pro-Gly-Phe-Met (SPGFM) using a protein / polypeptide sequencer (see Figure 6 ), and the molecular weight was detected by ESI / MS to be 537.6 Da (see Figure 7 ).

[0051] The hypotensive peptide Ser-Pro-Gly-Phe-Met (SPGFM) prepared above from the swim bladder of Thamnaconus septentrionalis was subjected to an ACE inhibitory activity experiment. The experimental results showed that the half inhibitory concentration (IC 50 ) of this polypeptide was 25.78 ± 1.36 μM.

[0052] The effect of Ser-Pro-Gly-Phe-Met (SPGFM) on human umbilical vein endothelial cells (HUVEC) and related indicators was evaluated with reference to the literature [Shuo-Lei Zheng, Qian-Bin Luo, Shi-Kun Suo, Yu-Qin Zhao, Chang-Feng Chi, Bin Wang. Preparation, identification, molecular docking study and protective function on HUVECs of novel ACE inhibitory peptides from protein hydrolysate of skipjack tuna muscle [J]. Mar. Drugs 2022, 20, 176]. The results showed that Ser-Pro-Gly-Phe-Met (SPGFM) had no obvious toxicity to HUVEC (see Figure 8 ), and can promote the release of endogenous relaxing factor nitric oxide (NO) and inhibit the production of endogenous contractile factor endothelin-1 (ET-1) in HUVEC cells (see Figure 9 and Figure 10 ), indicating that Ser-Pro-Gly-Phe-Met (SPGFM) has certain antihypertensive and regulatory functions on HUVEC cells.

[0053] Finally, it should be noted that the above is only a specific embodiment of the present invention. Obviously, the present invention is not limited to the above embodiment, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A leatherjacket fish swim bladder antihypertensive peptide, characterized in that, The amino acid sequence of the Thamnaconus modestus swim bladder antihypertensive peptide is Ser-Pro-Gly-Phe-Met (SPGFM), and the molecular weight determined by ESI-MS is 537.6 Da.

2. The preparation method of the Thamnaconus modestus swim bladder antihypertensive peptide according to claim 1, wherein It includes the following steps: 1) Pretreatment of Thamnaconus modestus swim bladder: Thaw the Thamnaconus modestus swim bladder, remove impurities, homogenize it to a paste in a tissue homogenizer, then add it to a NaOH solution and soak at 4°C for 9 - 12 h, filter, rinse the NaOH with distilled water, dry, add ethyl acetate according to 1 g:8 - 10 mL, and perform ultrasonic treatment at room temperature at 42 KHZ and 300 W for 15 - 20 min, centrifuge to remove the supernatant to obtain Thamnaconus modestus swim bladder powder; 2) Preparation of the enzymatic hydrolysate of filefish swim bladder: Add the above-mentioned filefish swim bladder powder to 0.05 mol / L glycine-NaOH buffer solution with pH 9.5, mix, adjust the pH value of the mixed solution to 6.5 - 7.5, adjust the temperature to 45 - 55 °C, add neutral protease at 5.0×10 4 U / g, and hydrolyze for 3 - 5 h; after placing the enzymatic hydrolysate in boiling water for 5 - 10 min, inactivate the enzyme activity; adjust the pH value of the mixed solution to 9.5 - 10.5, adjust the temperature to 40 - 45 °C, add alkaline protease at 5.0×10 4 U / g, and hydrolyze for 3 - 5 h; after placing the enzymatic hydrolysate in boiling water for 5 - 10 min, inactivate the enzyme activity; obtain the enzymatic hydrolysate of filefish swim bladder; 3) Ultrafiltration fractionation of Thamnaconus modestus swim bladder enzymolysis solution: Ultrafilter the Thamnaconus modestus swim bladder enzymolysis solution with 1 kDa, 5 kDa, and 10 kDa ultrafiltration membranes, respectively collect the components with molecular weights less than 1 kDa, 1 - 5 kDa, 5 - 10 kDa, and greater than 10 kD, measure the angiotensin-converting enzyme (ACE) inhibitory activity of each component, and the component with the highest ACE inhibitory activity is the ultrafiltered enzymolysis solution, which is freeze-dried to obtain the ultrafiltered enzymolysis product; 4) Preparation of Thamnaconus modestus swim bladder antihypertensive peptide: Purify the ultrafiltered enzymolysis product successively by Sephadex LH-20 column chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC) to obtain Thamnaconus modestus swim bladder antihypertensive peptide; Among them, the filefish in step 1) is Thamnaconus septentrionalis ( Thamnaconus modestus ); the concentration of the NaOH solution in step 1) is 0.05 mol / L, and the weight-to-volume ratio of the filefish swim bladder to the NaOH solution is 1 g:10 - 15 mL; the weight-to-volume ratio of the filefish swim bladder to ethyl acetate in step 1) is 1 g:8 - 10 mL; the concentration of the glycine-NaOH buffer solution in step 2) is 0.05 mol / L, and the pH is 9.5; the weight-to-volume ratio of the filefish swim bladder powder to the glycine-NaOH buffer solution in step 2) is 1 g:6 - 8 mL; the addition amount of neutral protease in step 2) is 1.0 - 2.0% of the mass of the filefish swim bladder powder; the addition amount of alkaline protease in step 2) is 1.0 - 2.0% of the mass of the filefish swim bladder powder; the hydroxypropyl dextran gel (Sephadex LH-20) chromatography purification and RP-HPLC purification in step 4) are as follows: Sephadex LH-20 column chromatography purification: Prepare the ultrafiltered enzymolysis product into a solution of 45 - 55 μg / mL, separate it by Sephadex LH-20 column chromatography, elute with double-distilled water, and collect the elution components according to the absorbance curve at 214 nm. Among them, the peak with the highest ACE inhibitory activity is the gel chromatography enzymolysis product, which is freeze-dried; RP-HPLC purification: Prepare the above Thamnaconus modestus swim bladder gel chromatography enzymolysis product into a solution of 90 - 100 μg / mL with double-distilled water, purify it by RP-HPLC, and obtain 1 highly active oligopeptide Ser-Pro-Gly-Phe-Met (SPGFM) according to the ACE inhibitory activity of the prepared oligopeptide, and the molecular weight determined by ESI-MS is 537.6 Da; the RP-HPLC conditions are as follows: injection volume 180 - 200 μL; chromatographic column Hypersil 300A C18: 250 mm × 10.0 mm, 10 μm; mobile phase: 60% acetonitrile; elution speed 1.5 - 2.0 mL / min; ultraviolet detection wavelength 214 nm.

3. Use of a Thamnaconus modestus swim bladder antihypertensive peptide as described in claim 1 in the preparation of a drug for treating hypertension.

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