Protein Determination Flashcards
How much of the blood serum protein dies albumin constitute?
Constitutes about half of the blood serum protein. It is soluble and monomeric
What is the function of albumin?
Transports hormones, fatty acids, and other compounds, buffer pH, and maintains osmotic pressure among other functions
What is the normal range of albumin?
Normal range is 3.4-5.4 grams per deciliter(g/dL)
What is the serum half-life of albumin? What is the molecular weight?
Half life is 20 days
It has molecular mass of 67 kDa
Why an albumin test?
Albumin is routinely included in the panels of tests performed as part of a physical, such as a comprehensive metabolic panel (CMP), so it is frequently asssessed as a part of an evaluation of a person’s overall health status
What can albumin be used to test?
Monitor changes in health status with treatment or with disease progression, and as a screen that may indicate the need for other kinds of testing
Albumin test may be ordered as part of a liver panel to evaluate liver function, along with a creatinine and blood urea nitrogen (BUN) to evaluate kidney function, or a,bog with a prealbumin test to evaluate a person’s nutritional status
What does low albumin indicate?
Suggest liver disease, other liver tests needed to know what type of liver disease
Low albumin levels can reflect diseases in which the kidneys can not prevent albumin from leaking from the blood into urine and being lost.
In this case, the amount of albumin (or protein) in the urine also may be measured
- can be seen in inflammation, shock, and malnutrition
- low albumin levels may also suggest conditions in which your body does not properly absorb and digest protein (like Crohn’s disease or sprue) or in which large volumes of protein are lost from the intestines
What does high albumin indicate?
- Usually reflect dehydration
- Certain drugs increase albumin in your blood, including anabolic steroids, androgens, growth hormones, and insulin
- If you are receiving large amounts of intravaneous fluids, the results of this test may be inaccurate
What is the biurette reagent made up of?
Sodium hydroxide and copper (II) sulphate
How does sodium hydroxide in biurette reagent work?
The sodium hydroxide doesn’t participate in the reaction, but provides an alkaline medium for the reaction to take place
- The Biurette test doesn’t detect free amino acids
- Compounds with 2 or more peptide bonds can be detected by this test
How does formation of the biuret reaction work in biuret reaction?
-formation of the biuret complex between protein and cupric ions shifts the color of solutions from blue to purple. This is called the biuret reaction.
Proteins complex with copper (II) (cupric) ions under alkaline conditions
The biuret reaction can be used to determine the amount of soluble protein in a solution, e.g. in serum, plasma, food substances etc.
What is the Spectrophotometry-Beer’s law?
The intensity of the color produced is directly proportional to the number of peptide bonds, and therefore the amount of protein present.
The amount of light absorbed is directly proportional to the amount (concentration) of protein present
What color is absorbed in the biuret complex?
The Biuret complex absorbs in the green-yellow region so the transmitted light will be purple (violet)
What are the other quantitative tests for protein?
- Bradford test
- Folin-Lowry test
- ultraviolet (UV) absorption at 280nm
