Protein concentration determination

Protein concentration determination is the determination of protein concentration by chemical or physical methods and is an important method often used to calculate the recovery rate of purification methods. The biuret method biuret method is the first method to determine the protein concentration by colorimetry. Sulfur ammonium does not interfere with color development, Cu2+ and protein peptide bonds, and tyrosine residues complex to form purple blue The compound has a maximum absorption at a wavelength of 540 nm. The biuret method is commonly used for the determination of protein solutions in the range of 0.5 g/L to 10 g/L. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Common in diseases such as malnutrition. Normal value: Normal value: 60-80g/L Above normal: Common in diseases such as obesity. negative: Positive: Tips: Do not eat too greasy, high-protein foods the day before, and avoid heavy drinking. Normal value The normal value of the human body is generally 60-80 g/L. Clinical significance Abnormal result 1. Biuret method: The biuret method is the first method to determine the protein concentration by colorimetry. Sulfur ammonium does not interfere with color development, Cu2+ and protein peptide bonds, and tyrosine residues complex, forming purple Blue complex, which has maximum absorption at a wavelength of 540 nm. The biuret method is commonly used for the determination of protein solutions in the range of 0.5 g/L to 10 g/L. 2. Lowry method: Cu+ forms a complex with protein in an alkaline solution, and then the complex reduces the phosphorus molybdenum phosphorus-phosphoric acid reagent (Folin-phenol reagent), and the result is a dark blue color. This method is much more sensitive than the biuret method and is suitable for the determination of protein solutions in the range of 20 mg/L to 400 mg/L. 3. Ultraviolet absorption method: Most proteins have the characteristic maximum absorption at 280nm wavelength. This is due to the presence of tyrosine, tryptophan and phenylalanine in the protein, which can be used to determine the content of 0.1-0.5mg/ml. Protein solution. People who need to be checked There are people who are weak and weak, sleepy, skin, mucous membranes, and inattention. Low results may be diseases: malnutrition, muscular dystrophy results may be high disease: obesity, simple obesity precautions Taboo before the test: Do not eat too greasy, high-protein foods the day before the test, to avoid heavy drinking. The alcohol content in the blood directly affects the test results. After 8 pm on the day before the medical examination, you should fast. Requirements for examination: When taking blood, you should relax your mind to avoid the contraction of blood vessels caused by fear and increase the difficulty of blood collection. In the measurement, a small amount of the protein-dye complex is adsorbed on the wall of the cuvette, and the amount of adsorption of the complex is negligible. After the measurement, the blue cuvette can be washed with ethanol. Inspection process Subjects were venously collected and assayed in time for serum separation. Draw a standard curve: Take a 96-well microtiter plate and add reagents. After the reagent is added, accurately absorb 20 μl of the sample solution into the enzyme standard well, add 200 μl of BCA reagent, shake gently, incubate at 37 ° C for 30-60 min, cool to room temperature, use blank as control, and compare at 590 nm on the microplate reader. Color, with the bovine serum albumin content as the abscissa and the absorbance as the ordinate, draw a standard curve. Using the standard curve blank as a control, the protein content of the sample was found from the standard curve based on the absorbance of the sample. Not suitable for the crowd People with a significant tendency to bleed. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.