Yeast active component detection method based on marker polypeptide and application of yeast active component detection method

Abstract

The invention provides a method for detecting active ingredients of yeast based on a marker polypeptide and application of the method, and belongs to the technical field of biological detection. The method comprises the following steps: preparing characteristic polypeptide standard solutions with different concentrations; preparing a to-be-detected sample solution; an optimized liquid chromatography-mass spectrometry (LC-MS / MS) condition is adopted for qualitative and quantitative analysis, and ion pairs of parent ions m / z 569.39 and daughter ions m / z 438.14 are specifically monitored. The enzymolysis pretreatment conditions including protease selection, enzymolysis temperature, pH value, time and enzyme substrate proportion are further optimized. The method has the advantages of strong specificity, high sensitivity, good stability and the like, and is suitable for yeast peptide raw material purity detection, production process monitoring and quality control of active components of a final product.

Description

Technical Field

[0001] The present invention relates to the field of biological detection technology, and in particular to a method for detecting yeast active ingredients based on characteristic polypeptides. Background Art

[0002] Yeast peptides are edible yeast peptides made from spent brewer's yeast through a process of filtration, crushing, washing, enzymatic hydrolysis, and filtration. Components with a molecular weight less than 1000 Da account for ≥94.88% of the peptides, and the primary amino acid is glutamic acid, at a concentration of 11.3g / 100g. As an important bioactive ingredient, yeast peptides are widely used in various fields, including medicine, food, and cosmetics. With their expanding application in functional products, accurate, sensitive, and standardized detection of these active ingredients has become a key technical challenge that urgently needs to be addressed.

[0003] However, the current detection methods for active characteristic peptides in yeast peptides still lack a standardized system. Common detection methods in the existing technology include enzyme-linked immunosorbent assay (ELISA), liquid chromatography (HPLC), and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The ELISA method relies on the specific recognition between antigens and antibodies for qualitative and quantitative analysis. Although it has a certain sensitivity, its operation steps are cumbersome, the cost is high, and it is prone to non-specific adsorption, which may produce false positive results. The SDS-PAGE method has poor specificity and is difficult to distinguish between yeast-derived peptides and other biological source peptides. It is also easily interfered by the sample matrix. Although conventional liquid chromatography has a certain separation ability, its detection sensitivity for low-abundance target peptides is limited, and it is difficult to meet the needs of trace analysis.

[0004] Furthermore, these traditional methods often suffer from complex operations, tedious pre-treatment steps, and lengthy testing times, making them difficult to adapt to the high-throughput, rapid-response industry testing needs. More importantly, many existing testing methods lack systematic methodological validation, and key parameters such as repeatability and precision are not fully evaluated, limiting their application in quality control and standardized testing.

[0005] To address these challenges, the present invention developed a highly specific and sensitive quantitative detection method for yeast active ingredients by screening for the unique characteristic peptide LGGPLL derived from yeast and combining it with optimized liquid chromatography and tandem mass spectrometry detection conditions. This method not only enhances the ability to identify target peptides but also completes methodological validation through steps such as standard curve construction, ion pair screening, and parameter verification, significantly improving detection efficiency and accuracy. This provides technical support for yeast peptide product quality evaluation, process optimization, and immunogenicity research. Summary of the Invention

[0006] To address the challenges of existing yeast peptide detection methods, such as insufficient specificity, low sensitivity, inconsistent methods, cumbersome procedures, and difficulty in standardization, the present invention provides a method for detecting yeast active ingredients based on the characteristic peptide LGGPLL. This method achieves accurate qualitative and quantitative detection of yeast-derived active ingredients through targeted identification of the characteristic peptide, combined with optimized liquid chromatography-mass spectrometry parameter settings. This method boasts significant technical benefits, including strong specificity, high sensitivity, broad sample adaptability, quantifiable results, and ease of standardized application. It can provide reliable support for quality control, process monitoring, and functional verification of yeast peptide products.

[0007] In one possible embodiment, a method for detecting yeast active ingredients based on characteristic polypeptides is provided, comprising the following steps:

[0008] S10, preparing a standard curve solution: preparing a yeast active characteristic polypeptide having an amino acid sequence of LGGPLL into standard solutions of different concentrations for subsequent quantitative analysis;

[0009] S20, preparing the test solution: dissolving the yeast peptide sample to be tested in 0.1 mol / L Tris-HCl buffer at pH 8.0, centrifuging at 10,000 rpm for 10 minutes, and collecting the supernatant as the test sample;

[0010] S30, performing liquid chromatography-mass spectrometry detection:

[0011] S301, liquid chromatography conditions: using a C18 reverse phase column, with a 0.1% formic acid aqueous solution and a 0.1% formic acid 60% acetonitrile aqueous solution as the mobile phases, and performing gradient elution to improve the separation of the polypeptide components;

[0012] S302, mass spectrometry conditions: In electrospray positive ionization mode, the ion pair of parent ion m / z 569.39 and product ion m / z 438.14 was monitored to specifically identify the target peptide;

[0013] S40, performing qualitative confirmation based on the retention time and characteristic ion pairs of LGGPLL in the detection spectrum, and quantitatively calculating its content in combination with the standard curve.

[0014] Furthermore, the gradient elution program is specifically as follows: 5% acetonitrile is maintained from 0 to 0.5 minutes, transitioning from 5% to 20% from 0.5 to 2 minutes, gradually increasing to 30% from 2 to 9 minutes, rapidly increasing to 90% from 9 to 9.1 minutes, maintaining 90% from 9.1 to 12 minutes, decreasing from 90% to 5% from 12 to 12.1 minutes, and maintaining 5% from 12.1 to 15 minutes. This gradient program can effectively improve the separation efficiency of small molecule peptides, reduce background interference, and enhance qualitative identification.

[0015] Furthermore, the mass spectrometry detection parameters were set as follows: ion source spray voltage of 3.5 kV, capillary temperature of 320°C, collision energy of 19 eV, and sheath gas flow rate of 19.5 mL / min. This optimized parameter combination maintained sensitivity while improving signal stability, facilitating accurate quantification of LGGPLL.

[0016] Furthermore, the concentration range of the standard curve solution is 0.25-10 μg / mL, which can cover the concentration range of the target polypeptide in common yeast peptide products, has strong adaptability, and is conducive to product batch comparison and compliance control.

[0017] In particular, the sample is a low-molecular-weight yeast peptide obtained by enzymatic hydrolysis of brewer's yeast, with a molecular weight of less than 1000 Da. This characteristic restriction enhances the method's adaptability to specific types of functional peptides, avoids interference from non-target peptides, and improves the specificity and interpretability of the test results.

[0018] In particular, the quantitative calculation in step S40 is performed according to the following formula: Here, Mi represents the active characteristic peptide content of yeast in the sample (μg / mg), X is the measured concentration (μg / mL), V is the fixed volume (mL), and m is the sample mass (mg). This formula allows calculation of the true sample content, avoids deviations caused by dilution errors, and improves quantitative accuracy and traceability.

[0019] Furthermore, this method can be applied to yeast peptide quality control, including yeast peptide raw material purity detection, process monitoring, and final product active ingredient content determination, significantly enhancing the quality supervision capabilities at all stages of production.

[0020] In particular, the glutamic acid content in the yeast peptide is greater than or equal to 11.3 g / 100 g. This indicator, as an important indicator of product functional activity, can be used to assist in evaluating product quality and consistency.

[0021] In one possible embodiment, a detection kit for performing the above-described detection method is provided. The kit comprises: a peptide standard having the amino acid sequence LGGPLL, a Tris-HCl buffer at pH 8.0, and a technical manual describing the detection steps. This kit enables rapid on-site deployment, simplifies the detection process, and facilitates the industrialization of the method.

[0022] Based on the above technical solution, the present invention provides a method for detecting yeast active ingredients based on characteristic peptides. By targeting and identifying a characteristic peptide fragment with the amino acid sequence LGGPLL and combining it with optimized liquid chromatography-mass spectrometry, it achieves specific qualitative and quantitative detection of functional active ingredients in yeast peptides. Compared with existing technologies, this method has the following significant technical advantages:

[0023] First, in terms of specific recognition capabilities, the present invention uses LGGPLL, a pre-screened yeast-derived peptide sequence, as a signature sequence. This sequence exhibits excellent source specificity and functional representativeness. By setting a dedicated ion transition m / z 569.39→438.14 and a retention time window, it is able to effectively identify key functional fragments within yeast peptides. This overcomes the inability of traditional methods such as SDS-PAGE and HPLC to distinguish between peptides from different biological sources, significantly improving the specificity of the assay.

[0024] Secondly, in terms of sensitivity and accuracy, the present invention optimizes the response intensity and resolution of target peptides through the optimized combination of chromatographic conditions and mass spectrometry parameters. In particular, through the establishment of a standard curve and ion-pair-directed screening, detection sensitivity at the μg / mL level is achieved. This method can be used for the detection of trace samples and is applicable to a variety of sample states, including raw materials, intermediates, and finished products. This overcomes the shortcomings of ELISA and conventional chromatography methods, such as their limited sensitivity and high false-positive rates.

[0025] Again, in terms of methodological stability and quantitative scientificity, the present invention further introduces a unified calculation formula The relationship between concentration, volume and mass is clearly defined, providing a rigorous mathematical model for calculating the content of target peptides, and improving the repeatability, comparability and industrial application stability of the results.

[0026] Furthermore, in terms of applicability and scalability, the detection process of this invention is applicable to a variety of sample formats, including lyophilized powder, liquid, and fermentation concentrate. Detection is not restricted by sample state, and the pre-treatment process is simple and easy to operate. Combined with the developed supporting kit, standardized testing deployment can be achieved, meeting the testing needs of enterprises at all stages, including R&D, quality control, and process scale-up.

[0027] In summary, the present invention not only fills the technical gap of insufficient standardization of targeted detection methods for yeast active peptides, but also provides a quantifiable, traceable, and industrializable solution for the quality evaluation, functional verification, and immunogenicity control of yeast peptide products, which has important application value and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly understand the technical solution of the present invention, the following describes the embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0029] Figure 1 This is the primary mass spectrum of the yeast-derived active characteristic peptide LGGPLL, showing the mass-to-charge ratio (m / z) distribution characteristics of its parent ion, with the main peak at m / z 569.39.

[0030] Figure 2 This is the secondary mass spectrum (MS / MS) of the yeast-derived active characteristic polypeptide LGGPLL under a collision energy of 19 eV, showing its characteristic product ion fragments after fragmentation, among which the product ion m / z 438.14 is the main monitored ion.

[0031] Figure 3 The chromatograms / mass spectra of LGGPLL standard solutions with different concentration gradients obtained under optimized liquid chromatography-mass spectrometry conditions reflect the linear relationship between concentration and signal response, supporting the construction of the standard curve.

[0032] Figure 4 This is the spectrum of the LGGPLL characteristic peptide detected in the yeast peptide sample. By comparing it with the standard spectrum, its retention time and ion pair characteristics are consistent, confirming that the sample contains the target characteristic peptide. DETAILED DESCRIPTION

[0033] The following examples further illustrate the technical solutions of the present invention and, in conjunction with the accompanying drawings, provide a detailed description of the method for quantitatively detecting a characteristic polypeptide of the present invention. However, the scope of the present invention is not limited to these embodiments. Reasonable modifications or equivalent substitutions may be made by those skilled in the art without departing from the essence of the present invention, and all such modifications and equivalent substitutions are intended to fall within the scope of the present invention.

[0034] Example 1: Detection of the content of yeast-derived active characteristic polypeptides in yeast peptides

[0035] This example aims to provide a method for accurately detecting the content of yeast-derived active characteristic polypeptides in yeast peptides. The specific implementation process and results of this detection method are described in detail below.

[0036] 1. Experimental Preparation

[0037] (1) Preparation of experimental reagents

[0038] Before conducting the yeast-derived active characteristic peptide content detection experiment in yeast peptides, various experimental reagents need to be prepared. Among them, the yeast peptide sample is the target substance to be detected, and it is necessary to ensure that its source is reliable and the storage conditions meet the requirements. Chromatographically pure acetonitrile was purchased from Merck in the United States. It has high purity and few impurities, and is suitable for the requirements of mobile phase organic solvents in liquid chromatography analysis. Chromatographically pure formic acid was purchased from Thermo Fisher in the United States and is used to adjust the pH value of the mobile phase to improve the ionization efficiency of the peptide in liquid chromatography and mass spectrometry analysis. In addition, other commercially available analytically pure reagents were also used in the experiment. These reagents are used for routine operations such as solution preparation and need to be stored and used in accordance with the requirements of the reagent instructions.

[0039] (2) Preparation of experimental instruments

[0040] The instrumentation used in the experiment is crucial to the accuracy and reliability of the test results. The AL104 analytical balance, manufactured by Mettler Toledo, offers high precision and stability, enabling precise weighing of yeast peptide samples and standards, ensuring the accuracy of the experimental data. The PK165 centrifuge, manufactured by Hunan Pingke Scientific Instrument Co., Ltd., was used to centrifuge the yeast peptide samples and separate the supernatant for subsequent analysis. The U3000 liquid chromatograph, manufactured by Thermo Fisher Scientific, USA, offers high separation performance and stable operation, enabling effective separation of peptides. The QuantumACCESS MAX triple quadrupole liquid chromatography-mass spectrometry (LC-MS / MS), also from Thermo Fisher Scientific, USA, combines the separation power of liquid chromatography with the qualitative and quantitative analysis capabilities of mass spectrometry, enabling accurate detection of active characteristic peptides derived from yeast. Xcalibur 3.1 data processing software was used to process and analyze the data collected by the LC-MS / MS, thereby calculating the peptide content.

[0041] 2. Preparation of standard solution

[0042] To quantitatively analyze the yeast-derived active peptide in yeast peptide samples, a series of standard working solutions must be prepared. First, using the analytical balance prepared above, accurately weigh 10 mg of the yeast-derived active peptide standard and place it in a 10 mL volumetric flask. Next, add an appropriate amount of 0.1 mol / L Tris-HCl (pH 8.0) solution to the flask. Gently shake to fully dissolve the standard, and then use this solution to dilute to the mark to obtain a stock solution of the yeast-derived active peptide standard. Next, dilute an appropriate amount of the stock solution with 0.1 mol / L Tris-HCl (pH 8.0) to prepare a series of standard working solutions with concentrations of 0.25 μg / mL, 0.5 μg / mL, 1 μg / mL, 2 μg / mL, 5 μg / mL, and 10 μg / mL, respectively. These standard working solutions will be used in subsequent liquid chromatography-mass spectrometry analysis to establish a standard curve for quantitative calculation of the peptide content in the sample.

[0043] 3. Processing of Yeast Peptide Samples

[0044] Place 5.0 mg of yeast peptide sample, accurately weighed, into a 15 mL centrifuge tube. Add 10 mL of 0.1 mol / L Tris-HCl (pH 8.0) solution. Gently shake the tube to thoroughly mix the sample and solution to ensure that the peptide in the sample is fully dissolved. Place the tube in a centrifuge and centrifuge at 10,000 rpm for 10 minutes. During centrifugation, insoluble matter in the sample will settle to the bottom of the tube, while the supernatant contains the peptide component to be detected. After centrifugation, carefully remove the supernatant with a pipette and transfer it to a clean container for subsequent liquid chromatography-mass spectrometry analysis.

[0045] 4. Quantitative Analysis

[0046] (1) Liquid chromatography analysis

[0047] The processed yeast peptide sample supernatant and the prepared standard working solution were sequentially injected into a liquid chromatograph for analysis. The liquid chromatograph used a Zorbax C18 column (2.1 mm × 150 mm, 5 μm), which exhibits excellent separation performance and selectivity, effectively separating the peptide components. The mobile phase consisted of phase A (water containing 0.1% formic acid) and phase B (60% acetonitrile in water, v / v, containing 0.1% formic acid). During the analysis, a gradient elution procedure was used, with the following details: from 0 to 0.5 min, the mobile phase B ratio was 5%; from 0.5 to 2 min, the mobile phase B ratio was linearly increased from 5% to 20%; from 2 to 9 min, the mobile phase B ratio was linearly increased from 20% to 30%; from 9 to 9.1 min, the mobile phase B ratio was rapidly increased from 30% to 90%; from 9.1 to 12 min, the mobile phase B ratio was maintained at 90%; from 12 to 12.1 min, the mobile phase B ratio was rapidly decreased from 90% to 5%; and from 12.1 to 15 min, the mobile phase B ratio was maintained at 5% to equilibrate the column and prepare for the next analysis. The liquid chromatograph flow rate was set at 0.2 mL / min, the column temperature was controlled at 30°C, and the sample load was 10.0 μL. Under these conditions, the peptide components were fully separated on the column and sequentially entered the mass spectrometer for analysis.

[0048] (2) Mass spectrometry analysis

[0049] The separated polypeptide components flowing out of the liquid chromatograph enter the triple quadrupole liquid chromatography-mass spectrometry instrument for mass spectrometry analysis. The ion source spray voltage of the mass spectrometer is set to 3.5kV to ionize the polypeptide. The capillary temperature is controlled at 320°C, which is conducive to the stable transmission of ions. The evaporation temperature is set to 350°C to promote the evaporation of the solvent and improve the ionization efficiency. The sheath gas flow rate is 19.5mL / min, and the auxiliary flow rate is 0.37bar, providing a stable environment for the ionization process. The mass spectrometer uses positive ion mode scanning, which is suitable for the analysis of polypeptides. In the SRM monitoring mode, for the active characteristic polypeptides derived from yeast, the monitoring parameters of m / z569.39 (single charge)→438.14 are set. Among them, the parent ion mass-to-charge ratio (m / z) of the LGGPLL characteristic polypeptide under the primary mass spectrometry is 569.39, and its mass spectrum is as shown below. Figure 1 The figure shows the characteristic peak position and intensity distribution of the ion. Tube Lens was set to 90° and CE was set to 19° to improve detection specificity and sensitivity. Mass spectrometry analysis can generate the mass spectrometry signal of the peptide, which, combined with the retention time of liquid chromatography, enables qualitative and quantitative analysis of the peptide.

[0050] (3) Data processing and content calculation

[0051] Data collected by the LC / MS instrument were processed using Xcalibur 3.1 data processing software. First, a standard curve was established based on the concentration of the standard working solution and the corresponding mass spectrometry signal intensity. The mass spectrometry signal intensity of the yeast peptide sample supernatant was then substituted into the standard curve to calculate the content of the yeast-derived active characteristic peptide in the sample. The final test result was averaged after analysis and calculation of multiple replicate samples to improve data accuracy and reliability.

[0052] 5. Experimental Results

[0053] (1) Methodological validation

[0054] The chromatograms of different concentrations of yeast-derived active characteristic peptide standard solutions are as follows: Figure 3 As shown (A, B, C, D, E, and F in the figure are active characteristic peptides derived from yeast with concentrations of 0.25 μg / mL, 0.5 μg / mL, 1 μg / mL, 2 μg / mL, 5 μg / mL, and 10 μg / mL, respectively), the secondary mass spectrum of the peptide is as shown Figure 2 By performing linear regression analysis on the concentration of the standard solution and the corresponding mass spectrometry signal intensity, the linear regression equation y=3,757,229.162x+4,757,383.167 was obtained, and the correlation coefficient R 2 =0.997. The linear correlation coefficient is greater than 0.99, indicating that the peptide has a good linear relationship within the concentration range tested and meets the requirements of quantitative analysis.

[0055] In the methodological investigation, a precision experiment was conducted. The standard solution of the same concentration was measured repeatedly, and its relative standard deviation (RSD) value was calculated. The result was 0.80%, indicating that the precision of the instrument was good and it could stably detect the content of the polypeptide. In the repeatability experiment, the same yeast peptide sample was processed and analyzed multiple times, and the calculated RSD value was 3.13%, indicating that the method has good repeatability and the difference in the analysis results of different batches is small. In addition, an addition recovery experiment was also carried out. At different addition levels, the addition recovery results were between 96% and 118%, which met the addition recovery requirements, indicating that the detection method can accurately detect the content of polypeptides in the sample. At the same time, the quantitative limit and detection limit of the characteristic polypeptide were determined to be 0.5ng / mL and 0.25ng / mL, respectively, through experiments, indicating that the method has high sensitivity and can detect low concentrations of polypeptide components.

[0056] (2) Measurement results

[0057] The active characteristic peptides from yeast in yeast peptide samples were detected. According to the above-established standard curve and data processing method, combined with the formula The content of yeast-derived active characteristic polypeptides was calculated. The results showed that the content of yeast-derived active characteristic polypeptides in the yeast peptide sample was 0.38±5.58%.

[0058] like Figure 4 As shown, the retention time and ion pair characteristics of the LGGPLL characteristic peptide detected in the yeast peptide sample are highly consistent with the standard spectrum, further verifying the presence of the target peptide in the sample and achieving its qualitative confirmation. Although there is a certain range of fluctuation in this result, combined with the results of methodological validation, it can be concluded that this detection method can relatively accurately reflect the content of yeast-derived active characteristic peptides in yeast peptide samples.

[0059] In summary, this example, through a series of rigorous experimental steps, accurately determined the content of yeast-derived active characteristic peptides in yeast peptides, and the reliability of the method was demonstrated through methodological validation. This method provides an effective analytical tool for quality control and related research of yeast peptides.

[0060] The above is a detailed description of the specific embodiments of the present invention, but the enumerated embodiments are only used to illustrate the basic principles and technical solutions of the present invention, and are not used to limit the scope of protection of the present invention. It should be understood by those skilled in the art that various modifications, replacements or improvements can be made to the above embodiments without departing from the spirit and scope of the present invention, and these modifications or variations all fall within the scope of protection of the present invention. The method of the present invention has high specificity, sensitivity and applicability, and is particularly suitable for quality control, process monitoring and standardized evaluation of yeast peptide products, and has good industrial application prospects.

Claims

1. A method for detecting yeast active ingredients based on characteristic polypeptides, characterized in that: The following steps are involved: S10, preparing a standard curve solution: preparing a yeast active characteristic polypeptide having an amino acid sequence of LGGPLL into standard solutions of different concentrations; S20, prepare the test solution: dissolve the yeast peptide sample to be tested in 0.1 mol / L Tris-HCl buffer at pH 8.0, centrifuge at 10,000 rpm for 10 minutes, and collect the supernatant; S30, performing liquid chromatography-mass spectrometry detection: S301, liquid chromatography conditions: using a C18 reverse phase column, gradient elution with an aqueous solution containing 0.1% formic acid and a 60% acetonitrile aqueous solution containing 0.1% formic acid as the mobile phase; S302. Mass spectrometry conditions: In electrospray positive ionization mode, monitor the ion pair of parent ion m / z 569.39 and product ion m / z 438.14; S40. Perform qualitative confirmation based on the retention time and characteristic ion pairs of LGGPLL in the detection spectrum, and quantitatively calculate its content in combination with the standard curve.

2. The method according to claim 1, characterized in that The gradient elution procedure in step S301 is: 0-0.5 min: 5% acetonitrile; 0.5-2 minutes: 5% to 20% acetonitrile; 2-9 minutes: 20% to 30% acetonitrile; 9-9.1 minutes: 30% to 90% acetonitrile; 9.1-12 minutes: maintain 90% acetonitrile; 12-12.1 minutes: 90% to 5% acetonitrile; 12.1-15 minutes: Equilibrate with 5% acetonitrile.

3. The method according to claim 1, characterized in that The mass spectrometry parameters of step S302 include: The ion source spray voltage was 3.5 kV; The capillary temperature is 320°C; The collision energy is 19 eV; The sheath gas flow rate was 19.5 mL / min.

4. The method according to claim 1, wherein The concentration range of the standard curve solution in step S10 is 0.25-10 μg / mL.

5. The method according to claim 1, wherein The sample in step S20 is a yeast peptide obtained by enzymatic hydrolysis, and has a molecular weight of less than 1000 Da.

6. The method according to claim 1, characterized in that The calculation formula for the content of the active characteristic polypeptide derived from yeast in step S40 is: in: Mi represents the content of active characteristic peptides derived from yeast in the sample, in μg / mg; X represents the measured concentration of active characteristic peptide derived from yeast, in μg / mL; V represents the final fixed volume of the sample, in mL; m represents the mass of the sample represented by the final sample solution, in mg.

7. Use of the detection method according to any one of claims 1 to 6 in yeast peptide quality control, characterized in that: By measuring the LGGPLL content, one or more of the following purposes can be achieved: Yeast peptide raw material purity testing; Yeast peptide production process monitoring; Determination of active ingredient content in yeast peptide final product.

8. The use according to claim 7, characterized in that The yeast peptide is a low-molecular-weight active peptide obtained by enzymatic hydrolysis of brewer's yeast, and the glutamic acid content is greater than or equal to 11.3 g / 100 g.

9. A detection kit for performing the detection method according to claim 1, characterized in that: Include: A peptide standard with the amino acid sequence of LGGPLL; Tris-HCl buffer, pH 8.0; A technical manual containing instructions for use of the detection method according to any one of claims 1 to 6.

Images