Please note: this site relies heavily on the use of javascript. Without a javascript-enabled browser, this site will not function correctly. Please enable javascript and reload the page, or switch to a different browser.
607  structures 109  species 8  interactions 1244  sequences 10  architectures

Family: Serum_albumin (PF00273)

Summary: Serum albumin family

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Albumin". More...

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This is the Wikipedia entry entitled "Serum albumin". More...

Serum albumin Edit Wikipedia article

ALB
ALB structure.png
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesALB, blood albumin, ANALBA, FDAH, PRO0883, PRO0903, PRO1341, albumin, Serum albumin, HSA
External IDsOMIM: 103600 MGI: 87991 HomoloGene: 405 GeneCards: ALB
Gene location (Human)
Chromosome 4 (human)
Chr.Chromosome 4 (human)[1]
Chromosome 4 (human)
Genomic location for ALB
Genomic location for ALB
Band4q13.3Start73,397,114 bp[1]
End73,421,482 bp[1]
RNA expression pattern
PBB GE ALB 211298 s at fs.png
More reference expression data
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_000477

NM_009654

RefSeq (protein)

NP_000468

NP_033784

Location (UCSC)Chr 4: 73.4 – 73.42 MbChr 5: 90.46 – 90.48 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Serum albumin, often referred to simply as blood albumin, is an albumin (a type of globular protein) found in vertebrate blood. Human serum albumin is encoded by the ALB gene.[5][6][7] Other mammalian forms, such as bovine serum albumin, are chemically similar.

Serum albumin is produced by the liver, occurs dissolved in blood plasma and is the most abundant blood protein in mammals. Albumin is essential for maintaining the oncotic pressure needed for proper distribution of body fluids between blood vessels and body tissues; without albumin, the high pressure in the blood vessels would force more fluids out into the tissues. It also acts as a plasma carrier by non-specifically binding several hydrophobic steroid hormones and as a transport protein for hemin and fatty acids. Too much or too little circulating serum albumin may be harmful. Albumin in the urine usually denotes the presence of kidney disease. Occasionally albumin appears in the urine of normal persons following long periods of standing (postural albuminuria).

Function

Albumin functions primarily as a carrier protein for steroids, fatty acids, and thyroid hormones in the blood and plays a major role in stabilizing extracellular fluid volume by contributing to oncotic pressure (known also as colloid osmotic pressure) of plasma.

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

Synthesis

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.[7]

Properties

Albumin is a globular, water-soluble, un-glycosylated serum protein of approximate molecular weight of 65,000 Daltons.

Albumin (when ionized in water at pH 7.4, as found in the body) is negatively charged. The glomerular basement membrane is also negatively charged in the body; some studies suggest that this prevents the filtration of albumin in the urine. According to this theory, that charge plays a major role in the selective exclusion of albumin from the glomerular filtrate. A defect in this property results in nephrotic syndrome leading to albumin loss in the urine. Nephrotic syndrome patients are sometimes given albumin to replace the lost albumin.

Structure

The general structure of albumin is characterized by several long α helices allowing it to maintain a relatively static shape, which is essential for regulating blood pressure.

Serum albumin contains eleven distinct binding domains for hydrophobic compounds. One hemin and six long-chain fatty acids can bind to serum albumin at the same time.[8]

Serum albumin family
PDB 1o9x EBI.jpg
Structure of human serum albumin.[9]
Identifiers
SymbolSerum_albumin
PfamPF00273
Pfam clanCL0282
InterProIPR014760
SMARTSM00103
PROSITEPS51438
SCOPe1ao6 / SUPFAM

Types

Serum albumin is widely distributed in mammals.

  • The human version is human serum albumin.
  • Bovine serum albumin, or BSA, is commonly used in immunodiagnostic procedures, clinical chemistry reagents, cell culture media, protein chemistry research (including venom toxicity), and molecular biology laboratories (usually to leverage its non-specific protein binding properties).

See also

References

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000163631 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000029368 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Hawkins JW, Dugaiczyk A (1982). "The human serum albumin gene: structure of a unique locus". Gene. 19 (1): 55–8. doi:10.1016/0378-1119(82)90188-3. PMID 6292049.
  6. ^ Harper ME, Dugaiczyk A (July 1983). "Linkage of the evolutionarily-related serum albumin and alpha-fetoprotein genes within q11-22 of human chromosome 4". American Journal of Human Genetics. 35 (4): 565–72. PMC 1685723. PMID 6192711.
  7. ^ a b "Entrez Gene: albumin".
  8. ^ Zunszain PA, Ghuman J, Komatsu T, Tsuchida E, Curry S (July 2003). "Crystal structural analysis of human serum albumin complexed with hemin and fatty acid". BMC Structural Biology. 3: 6. doi:10.1186/1472-6807-3-6. PMC 166163. PMID 12846933.
  9. ^ Sugio S, Kashima A, Mochizuki S, Noda M, Kobayashi K (June 1999). "Crystal structure of human serum albumin at 2.5 A resolution". Protein Engineering. 12 (6): 439–46. doi:10.1093/protein/12.6.439. PMID 10388840.

External links


This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Serum albumin family Provide feedback

No Pfam abstract.

Literature references

  1. He XM, Carter DC; , Nature 1992;358:209-215.: Atomic structure and chemistry of human serum albumin. PUBMED:1630489 EPMC:1630489


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR014760

A number of serum transport proteins are known to be evolutionarily related, including albumin, alpha-fetoprotein, vitamin D-binding protein and afamin [PUBMED:2481749, PUBMED:2423133, PUBMED:7517938]. Albumin is the main protein of plasma; it binds water, cations (such as Ca2+, Na+ and K+), fatty acids, hormones, bilirubin and drugs - its main function is to regulate the colloidal osmotic pressure of blood. Alphafeto- protein (alpha-fetoglobulin) is a foetal plasma protein that binds various cations, fatty acids and bilirubin. Vitamin D-binding protein binds to vitamin D and its metabolites, as well as to fatty acids. The biological role of afamin (alpha-albumin) has not yet been characterised. The 3D structure of human serum albumin has been determined by X-ray crystallography to a resolution of 2.8A [PUBMED:1630489]. It comprises three homologous domains that assemble to form a heart-shaped molecule [PUBMED:1630489]. Each domain is a product of two subdomains that possess common structural motifs [PUBMED:1630489]. The principal regions of ligand binding to human serum albumin are located in hydrophobic cavities in subdomains IIA and IIIA, which exhibit similar chemistry. Structurally, the serum albumins are similar, each domain containing five or six internal disulphide bonds, as shown schematically below:
                    +---+          +----+                        +-----+
                    |   |          |    |                        |     |
 xxCxxxxxxxxxxxxxxxxCCxxCxxxxCxxxxxCCxxxCxxxxxxxxxCxxxxxxxxxxxxxxCCxxxxCxxxx
   |                 |       |     |              |               |
   +-----------------+       +-----+              +---------------+

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

Loading domain graphics...

Pfam Clan

This family is a member of clan Serum_albumin (CL0282), which has the following description:

This superfamily includes serum albumin and related families.

The clan contains the following 2 members:

Serum_albumin VitD-bind_III

Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the UniProtKB sequence database, the NCBI sequence database, and our metagenomics sequence database. More...

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

  Seed
(172)
Full
(1244)
Representative proteomes UniProt
(1993)
NCBI
(3732)
Meta
(0)
RP15
(112)
RP35
(328)
RP55
(794)
RP75
(1001)
Jalview View  View  View  View  View  View  View  View   
HTML View  View               
PP/heatmap 1 View               

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(172)
Full
(1244)
Representative proteomes UniProt
(1993)
NCBI
(3732)
Meta
(0)
RP15
(112)
RP35
(328)
RP55
(794)
RP75
(1001)
Alignment:
Format:
Order:
Sequence:
Gaps:
Download/view:

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

  Seed
(172)
Full
(1244)
Representative proteomes UniProt
(1993)
NCBI
(3732)
Meta
(0)
RP15
(112)
RP35
(328)
RP55
(794)
RP75
(1001)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download    
Gzipped Download   Download   Download   Download   Download   Download   Download   Download    

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Prosite
Previous IDs: transport_prot;
Type: Domain
Sequence Ontology: SO:0000417
Author: Finn RD
Number in seed: 172
Number in full: 1244
Average length of the domain: 167.40 aa
Average identity of full alignment: 26 %
Average coverage of the sequence by the domain: 83.44 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 45638612 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 34.4 34.4
Trusted cut-off 34.6 36.3
Noise cut-off 32.9 34.3
Model length: 176
Family (HMM) version: 20
Download: download the raw HMM for this family

Species distribution

Sunburst controls

Hide

Weight segments by...


Change the size of the sunburst

Small
Large

Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence

Selections

Align selected sequences to HMM

Generate a FASTA-format file

Clear selection

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

Loading sunburst data...

Tree controls

Hide

The tree shows the occurrence of this domain across different species. More...

Loading...

Please note: for large trees this can take some time. While the tree is loading, you can safely switch away from this tab but if you browse away from the family page entirely, the tree will not be loaded.

Interactions

There are 8 interactions for this family. More...

VitD-bind_III GA VitD-bind_III Actin Serum_albumin Ig_2 Actin MHC_I

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Serum_albumin domain has been found. There are 607 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

Loading structure mapping...