Instructions for the Biuret Protein Content Determination Kit

Micro method 100T/96S

Attention: Select before formal testing 2-3 Make predictions for samples with significant expected differences to ensure protein concentration is within 1～10mg/ml scopeInside.

Measurement significance:

The soluble protein content of the sample is often used for enzyme activity calculation. In addition, soluble protein content is also used for quality analysis of food and other products.

Measurement principle:

In strongly alkaline solutions, biuret and CuSO4 Form a purple complex; The depth of the color of the purple complex is directly proportional to the concentration of the protein, whileProtein molecular weight and amino acid composition are independent, so they can be used to determine protein content. The measurement range of this method is 1~10mg Protein, suitable for samples with high protein concentration, especially animal materials.

Biuret protein content determination kit - readily available in stock

composition

Standard: Liquid 1ml×1 Bottle,5 mg/ml，4℃preservation.

Bring your own instruments and supplies：

Centrifuge, visible spectrophotometer/ELISA reader, trace quartz colorimetric dish/96 Orifice plate, pipette, and distilled water.

The specific product parameters are subject to the parameters in the product manual received

Extraction of soluble proteins from samples:

1. Liquid sample:Clear and colorless liquid samples can be directly measured.

2. Organizational samples:According to organizational quality（g) Volume of extraction solution (ml)for 1：5~10 The proportion of（Suggest weighing the agreement 0.1g Organize, join 1mlExtraction solution (self prepared, choose enzyme extraction buffer, distilled water or physiological saline as needed)））

Ice bath homogenate,8000g，4℃centrifugation 10min， Take the supernatant, which is the test solution. Animal samples often need to be diluted）

3 Bacteria and fungi: according to the number of cells（104)Volume of extraction solution（ml）for A ratio of 500~1000:1（suggestion 5 million cellsjoin 1ml Extraction solution), ice bath ultrasonic disruption of cells（power 300w, Ultrasound 3 Seconds, intervals 7 Second, total time 3min）；then 8000g，

4℃, centrifugation 10minTake the supernatant and place it on ice for testing.

Measurement operation:

1. spectrophotometer/Preheating of ELISA reader 30 minAdjust the wavelength to 540 nmAdjust distilled water to zero.

2. Blank tube:取 0.5mL EP Tube, join in 40μl distilled water200μl Reagent 1, mix well and let it stand at room temperature 15 min， 取 200μl In trace amountsGlass colorimetric dish/96 Orifice plate,540nm Color comparison, denoted asA Blank tube.

3. Standard tube:取 0.5mL EP Tube, join in 40μl Standard solution,200μl Reagent 1, mix well and let it stand at room temperature 15 min， 取 200μl Micro glass colorimetric dish/96 well plate, 540 nmColor comparison, denoted as A standard tube.

4. Measurement tube:取 0.5mL EP Tube, join in 40μl The liquid to be tested,200μl Reagent 1, mix well and let it stand at room temperature 15 min， 取 200μl In trace amountsGlass colorimetric dish/96 Orifice plate,540nm Color comparison, denoted asA Measurement tube.

Note: Blank tubes and standard tubes only need to be measured once.

Formula for calculating protein concentration in samples:

C To be tested（mg/ml）=C Standard tube×(A Measurement tube -A Blank tube)÷(A Standard tube -A Blank tube)

=5×(A Measurement tube -A Blank tube)÷(A Standard tube -A Blank tube)

Precautions:

1. The protein concentration of the sample must be within 1～10mg/mlWithin the range, below 1mg/mlCannot use this method, higher than 10mg/ml requires corresponding dilution. Therefore, testingPre order use 1~2Conduct a preliminary experiment to ensure that the protein concentration is within Within the range of 1-10mg/ml.

2. Protein extraction from the test sample can be done using physiological saline, double distilled water, or protein free solutions PBS Extract. This method is affected by ammonium sulfateTris Buffer interference, liftingThe liquid should not contain these substances; Otherwise, use it insteadBCA protein content determination kit.

Biuret protein content determination kit - readily available in stock