Human serum albumin

human serum albumin
PDB rendering based on 1e7h.
Identifiers
Symbol	ALB
Entrez	213
HUGO	399
OMIM	103600
PDB	1E7H
RefSeq	NM_000477
UniProt	P02768
Other data
Locus	Chr. 4 q13.3

Human serum albumin is the serum albumin found in human blood. It is the most abundant protein in human blood plasma; it constitutes about half of serum protein. It is produced in the liver. It is soluble and monomeric.

Albumin transports hormones, fatty acids, and other compounds, buffers pH, and maintains oncotic pressure, among other functions.

Albumin is synthesized in the liver as preproalbumin, which has an N-terminal peptide that is removed before the nascent protein is released from the rough endoplasmic reticulum. The product, proalbumin, is in turn cleaved in the Golgi vesicles to produce the secreted albumin.

The reference range for albumin concentrations in serum is approximately 35 - 50 g/L (3.5 - 5.0 g/dL). It has a serum half-life of approximately 20 days. It has a molecular mass of 66.5 kDa.

The gene for albumin is located on chromosome 4 and mutations in this gene can result in anomalous proteins. The human albumin gene is 16,961 nucleotides long from the putative 'cap' site to the first poly(A) addition site. It is split into 15 exons that are symmetrically placed within the 3 domains thought to have arisen by triplication of a single primordial domain.

Serum albumin is commonly measured by recording the change in absorbance upon binding to a dye such as bromocresol green or bromocresol purple.

Serum albumin concentration is typically 35 - 50 g/L (3.5 - 5.0 g/dL)

Hypoalbuminemia is a low blood albumin levels. This can be caused by:

Hyperalbuminemia is an increased concentration of albumin in the blood. Typically, this condition is due to abrupt dehydration.

Chronic dehydration needs to be treated with zinc as well as with water. Zinc reduces cell swelling caused by decreased intake of water (hypotonicity) and also increases retention of salt. In the dehydrated state, the body has too high an osmolarity and, it appears, discards zinc to prevent this. Zinc also regulates transport of the cellular osmolyte taurine, and albumin is known to increase cellular taurine absorption. Zinc has been shown to increase retinol (vitamin A) production from beta-carotene, and in lab experiments retinol reduced human albumin production. It is possible that a retinol (vitamin A) deficiency alone could cause albumin levels to become raised. Patients recovering from chronic dehydration may develop dry eyes as the body uses up its vitamin A store. Retinol causes cells to swell with water (this is most likely one reason that too much vitamin A is toxic). Hyperalbuminemia is also associated with high protein diets.