Albumin
What Is Albumin?
Albumin, or serum albumin, is a common protein in blood plasma and serum. The protein is a 66.5 kilodalton protein with many disulfide bonds. It is highly soluble and carries a strong negative charge.
The Functions of Albumin
Transports Cell Nutrients and Other Molecules
Albumin carries important substances throughout the body by acting as a binding agent. The important substances transported by albumin include certain steroid hormones, essential fatty acids, trace minerals, vitamin D and iron in the form of hemin. Albumin also transports some pharmaceutical drugs like antibiotics and anti-inflamatories, hence its frequent use in drug delivery.
Binds Other Proteins and Toxins
Since albumin non-specifically binds many proteins, it plays a role in many processes. It binds toxins to avoid toxic effects, binds excessive proteins to act as a buffer, binds hormones and growth peptides to keep them stable and binds free radicals to reduce damage to cells. In binding to itself and other proteins, it contributes to blood coagulation for wound healing.
Regulates Osmotic Pressure
Albumin regulates osmosis, maintains blood pressure and influences movement of fluids in and out of tissues and areas within the vascular system. This is important for fluid balance throughout the body. Edema or water collection in the tissues occurs when there is a dysregulation of albumin and is a sign of many chronic or potentially fatal illnesses, such congestive heart failure. Hence, it is used as a marker in a multitude of health tests to measure kidney and liver function.
The Uses of Albumin
A Cell Culture Media Additive
Serum albumin is used throughout the field of molecular biology as an additive to cell culture media. Albumin is a natural component of serum that supports the health and growth of cells. In serum-free media albumin improves cell growth and is often used in place of fetal bovine serum (FBS).
A Blocking Agent and Protein Stabilizer
Albumin is a common blocking agent because of its binding properties. It can greatly reduce contaminating binding that can interfere in common molecular biology assays. It is also used as a blocking agent in many other clinical applications like diagnostic procedures, medical devices and surgical stents. Albumin helps stabilize other proteins in solution.
Binding Applications
Albumin is used in many implantable biomaterials, surgical adhesives and surgical sealants due to its ability to coagulate. Its conjugation seals and binds in a way that few other biomaterials can.
Importance of Albumin
Serum albumin is used in many clinical applications for burn victims, hemorrhages, malnourishment and liver or kidney failure. There are often clinical shortages of human serum albumin (HSA) worldwide. As effective as albumin is, there is a risk of disease transmission when using human serum albumin clinically though, since it is derived from human blood.
Another source of albumin is bovine serum albumin (BSA). Bovine serum albumin can have great variability in albumin content from lot to lot due to the environment and diet of the animal sources. This variation often leads to variation in experimental results.
There are research studies and clinical applications that require the use of human serum albumin (HSA), where using BSA or a substitute will not work. Safety concerns regarding disease transmission has led to the development of techniques to make recombinant HSA in an animal-free production system.
References:
Asghar RB, Ann MD, Spanel P, Smith D, Simon JD. (2003). Measuring transport of water across the peritoneal membrane. Kidney International, 64(5):1911-5.
Bertucci C, Domenici E. (2002). Reversible and covalent binding of drugs to human serum albumin: methodological approaches and physiological relevance. Current Medicinal Chemistry, 9:1463-81.
Bird SM. (2004). Recipients of blood or blood products "at vCJD risk". British Medical Journal, 328:118-9.
Bucova M, Bernadic M, Buckingham T. (2008). C-reactive protein, cytokines and inflammation in cardiovascular diseases. Bratislavské Lekárske Listy, 109(8):333-40.
Chuang VT, Kragh-Hansen U, Otagiri M. (2002). Pharmaceutical strategies utilizing recombinant human serum albumin. Pharmaceutical Research, 19:569-77.
Fernández-San Millán A, Angel Mingo-Castel, Miller M, Daniell H. (2003). A chloroplast transgenic approach to hyper-express and purify human serum albumin, a protein highly susceptible to proteolytic degradation. Plant Biotechnology Journal, 1(2):71-9.
Koh S, Means G. (1979). Characterization of a small apolar anion binding site of human serum albumin. Archives Biochemistry Biophysics, 192:73-79.
Llewelyn CA, Hewitt PE, Knight RS, Amar K, Cousens S, Mackenzie J, Will RG. (2004). Possible transmission of variant Creutzfeldt-Jakob disease by blood transfusion. Lancet, 363: 417-21.
Martin L. (2004). Human albumin solutions in the critical patient. IVECCS Proceedings, 274-278.
Mitzner SR, Klammt S, Peszynski P, Hickstein H, Korten G, Stange J, Schmidt R. (2001). Improvement of multiple organ functions in hepatorenal syndrome during albumin dialysis with the molecular adsorbent recirculating system. Therapeutic Apheresis and Dialysis, 5(5):417-22.
Neuzil J, Stocker R. (1994). Free and albumin-bound bilirubin are efficient co-antioxidants for alpha-tocopherol, inhibiting plasma and low density lipoprotein lipid peroxidation. Journal of Biological Chemstry, 269:16712-9.
Peters T. (1995). All about albumin: biochemistry, genetics, and medical application. Academic Press, San Diego.
Petitpas I, Bhattacharya A, Twine S, East M, Curry S. (2001). Crystal structure analysis of warfarin binding to human serum albumin. Journal of Biological Chemistry, 276:22804-22809.
Richieri G, Anel A, Kleinfeld A. (1993). Interaction of long-chain fatty acids and albumin: determination of free fatty acid levels using the fluorescent probe ADIFAB. Biochemistry, 32:7574-7580.
Sudlow G, Birkett D, Wade D. (1975). The characterization of two specific drug binding sites on human serum albumin. Molecular Pharmacology, 11:824-832.
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