Napeptide with antioxidant activity

Abstract

The invention discloses a nonapeptide with antioxidant activity, the amino acid sequence of the nonapeptide is amino terminal-NTYLHKLVG-carboxyl terminal, and the nonapeptide can be developed into an antioxidant.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of peptide biotechnology, and particularly relates to a nine-peptide with antioxidant activity. BACKGROUND

[0002] Excessive accumulation of reactive oxygen species (ROS) can trigger oxidative stress. Under normal physiological conditions, the antioxidant defense system of the human body can maintain the dynamic balance of ROS content. However, with the increase of age and the stimulation of external environmental factors (such as pollution, radiation, improper diet, mental stress, etc.), the production and clearance process of ROS is imbalanced, leading to cell oxidative stress damage, thereby inducing Alzheimer's disease, hypertension, Parkinson's syndrome, cancer and other chronic diseases. Studies have shown that antioxidant peptides as a supplement to antioxidants can effectively scavenge excess ROS and reduce oxidative stress damage, and show good application potential in the prevention and treatment of oxidative stress-related diseases. In recent years, food-derived antioxidant peptides have attracted more and more research attention due to their wide sources, high safety, low toxicity and good biological activity. Developing food-derived peptides as dietary antioxidants has important application value and market prospect. SUMMARY

[0003] The present application provides a nine-peptide with antioxidant activity, and the amino acid sequence thereof is: amino-terminal-NTYLHKLVG-carboxyl-terminal, which can be developed as an antioxidant. BRIEF DESCRIPTION OF DRAWINGS

[0004] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings, in which:

[0005] Figure 1 is a mass spectrum of the antioxidant nine-peptide NTYLHKLVG.

[0006] Figure 2 is an HPLC graph of the antioxidant nine-peptide NTYLHKLVG.

[0007] Figure 3 is an ABTS free radical scavenging capacity determination graph of the antioxidant nine-peptide NTYLHKLVG. DETAILED DESCRIPTION

[0008] A series of polypeptide sequences are separated and identified from the enzymatic hydrolysate of duck embryos, and the present application peptide is identified. The antioxidant activity thereof is detected by ABTS free radical scavenging experiment.

[0009] Specific operation is: select healthy fertilized duck eggs after 15 days of incubation sample, homogenate and freeze-drying, grinding after degreasing 3-5 times with petroleum ether, then reconstituted with 0.9% saline, centrifugation and filtration with ≤3kDa ultrafiltration membrane, freeze-drying to obtain low molecular weight duck embryo polypeptide powder. Take part of the freeze-dried powder liquid nitrogen grinding, ultrasonic crushing 3-8min, centrifugal collection supernatant after precipitated twice with cold acetone (containing 10mM DTT), air-drying after dissolving with 8M Urea (containing 50mM Tris buffer, pH = 8), quantitative protein. Take 30ug protein for SDS-PAGE detection relative molecular weight. Again take 100ug protein plus trypsin (0.3% formic acid dissolution, 1ug / ul) and 0.1M triethylamine-carbonate buffer, 37 degrees C enzymolysis 16h, C18 desalination, LC-MS / MS analysis, identified to obtain the peptide, the amino acid sequence is: amino terminal-NTYLHKLVG-carboxyl terminal.

[0010] The peptide is artificially synthesized by polypeptide synthesizer, and the peptide segment prepared by the application has a molecular weight of 1044.20 Da, as shown in Figure 1 , and a purity of 99.05%, as shown in Figure 2 , which can be used for subsequent detection.

[0011] The IC50 value of ABTS free radical scavenging capacity is used as the antioxidant index, and the antioxidant activity is detected. The ABTS free radical scavenging capacity determination process is as follows: ABTS and potassium persulfate solution are mixed at 1:1, avoid light for 12h, generate ABTS free radical cation, then diluted with phosphate buffer (pH = 6.6), adjust the absorbance at 734nm to 0.7±0.2; take 0.2mL different concentration sample solution and 2mL ABTS working solution, mix in the incubator, avoid light reaction for 6min, measure the absorbance at 734nm As. At the same time, the absorbance of the blank experiment is measured by replacing ABTS working solution with phosphate buffer, and the absorbance of the control experiment is measured by replacing sample solution with distilled water. The ABTS free radical scavenging rate is calculated by the following formula:

[0012]

[0013] In the formula: Ac- control group absorbance;

[0014] As- sample group absorbance

[0015] Ab- blank group absorbance.

[0016] From Figure 3It can be concluded that the IC50 value of the peptide in the ABTS free radical scavenging experiment is 13.14 μg / mL, indicating that the peptide has high antioxidant activity, and the amino acid sequence thereof is: amino-terminal-NTYLHKLVG-carboxyl-terminal.

[0017] The above merely illustrates the preferred embodiments of the present application, and is not intended to limit the present application. Obviously, various modifications and variations of the present application can be made by those skilled in the art without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application claims and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A nonapeptide with antioxidant activity, characterized in that... Its amino acid sequence is: amino-terminal -NTYLHKLVG-carboxyl-terminal.

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