Albumin

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You may be looking for albumen, or egg white.

{{Protein

  |Name=Albumin
  |image=ALB_structure.png
  |caption=The structure of ALB complexed with 6 palmitic acid molecules
(from Template:PDB)
  |Symbol=ALB
  |AltSymbols=
  |HGNCid=399
  |Chromosome=4
  |Arm=q
  |Band=13.3
  |LocusSupplementaryData=
  |ECnumber=
  |OMIM=103600
  |EntrezGene=213
  |RefSeq=NM_000477
  |UniProt=P02768

}}

Albumin (Latin: albus, white) refers generally to any protein with water solubility, which is moderately soluble in concentrated salt solutions, and experiences heat coagulation (protein denaturation). Substances containing albumin, such as egg white, are called albuminoids. The term also refers to a specific blood plasma protein that is produced in the liver and forms a large proportion of all plasma protein. Albumin normally constitutes about 60% of human plasma protein; all other proteins present in blood plasma are referred to collectively as globulins. Human serum albumin is the human version.

Albumin is essential for maintaining the oncotic pressure needed for proper distribution of body fluids between intravascular compartments and body tissues. Albumin is negatively charged. The glomerular basement membrane is also negatively charged; this prevents the filtration of albumin in the urine. In nephrotic syndrome, this property is lost, and there is more albumin loss in the urine. Nephrotic syndrome patients are given albumin to replace the lost albumin.

Because smaller animals (for example rats) function at a lower blood pressure, they need less oncotic pressure to balance this, and thus need less albumin to maintain proper fluid distribution.

1 Functions of albumin
2 Causes of albumin deficiency (hypoalbuminemia)
3 Testing for albumin loss via the kidneys
4 External links

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Functions of albumin

Maintains osmotic pressure
Transports thyroid hormones
Transports other hormones, particularly fat soluble ones
Transports fatty acids ("free" fatty acids)
Transports unconjugated bilirubin
Transports many drugs
Competitively binds calcium ions (Ca²⁺)
Buffers pH

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Causes of albumin deficiency (hypoalbuminemia)

Cirrhosis of the liver (most commonly)
Decreased production (as in starvation)
Excess excretion by the kidneys (as in nephrotic syndrome)
Excess loss in bowel (protein losing enteropathy)
Mutation causing analbuminemia (very rare)
Acute disease states (referred to as a negative acute phase reactant)

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Testing for albumin loss via the kidneys

In the healthy kidney, albumin's size and negative electric charge exclude is from excretion in the glomerulus. In some diseases including diabetic nephropathy, a major complication of uncontrolled diabetes. The lost albumin can be detected by a simple urine test [1]. Depending on the amount of albumin lost, a patient may have normal renal function, microalbuminuria, or albuminuria.

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