protein
Albumin
Gene
ALB
Organism
Homo sapiens(9606)
Length
609 aa
Mass
69,367 Da
Albumin (ALB) is the most abundant plasma protein, serving multiple transport and regulatory functions. It binds diverse ligands including water, ions (calcium, magnesium, zinc), fatty acids, hormones, and bilirubin, and regulates blood colloidal osmotic pressure (UniProt: P02768). As the major zinc transporter in plasma, albumin typically binds approximately 80% of circulating zinc, with a binding affinity rank order of zinc > calcium > magnesium.
Albumin is primarily synthesized in the liver and circulates in blood, though its presence in cerebrospinal fluid and brain tissue reflects its role in systemic mineral and ligand homeostasis. Genetic variants in ALB cause rare disorders including familial dysalbuminemic hyperthyroxinemia and analbuminemia, characterized by altered thyroid hormone or severe albumin deficiency (UniProt: P02768).
In Alzheimer's disease, albumin is significantly down-regulated in post-mortem AD brain tissue compared to age-matched controls (mean log2 fold-change: −0.87) across multiple subcellular fractions (Chaparral AD proteomics). This reduction may reflect altered systemic-central nervous system transport or local brain metabolic changes associated with neurodegeneration, though the mechanistic significance requires further investigation.
Generated from the curated entity record below. May contain errors — verify against source links.
Proteomics Evidence · AD
↓ Down in ADP3
-1.127
P2
-1.026
S2
not detected
S3
-0.454
Mean log₂FC across detected fractions: -0.8689 (3 of 4 fractions detected)
Human post-mortem AD brain vs age-matched controls, TMT-labeled, 4 subcellular fractions (P2, P3, S2, S3), DDA proteomics.
Related Publications
Browse all →Tau molecular diversity contributes to clinical heterogeneity in Alzheimer's disease.
Dujardin Simon et al.Nature medicine2020PMID 32572268Deep Multilayer Brain Proteomics Identifies Molecular Networks in Alzheimer's Disease Progression.
Bai Bing et al.Neuron2020PMID 31926610A Multi-network Approach Identifies Protein-Specific Co-expression in Asymptomatic and Symptomatic Alzheimer's Disease.
Seyfried Nicholas T et al.Cell systems2017PMID 27989508Large-scale deep multi-layer analysis of Alzheimer's disease brain reveals strong proteomic disease-related changes not observed at the RNA level.
Johnson Erik C B et al.Nature neuroscience2022PMID 35115731Organization and regulation of gene transcription.
Cramer PatrickNature2019PMID 31462772
Function
Binds water, Ca(2+), Na(+), K(+), fatty acids, hormones, bilirubin and drugs (Probable). Its main function is the regulation of the colloidal osmotic pressure of blood (Probable). Major zinc transporter in plasma, typically binds about 80% of all plasma zinc (PubMed:19021548). Major calcium and magnesium transporter in plasma, binds approximately 45% of circulating calcium and magnesium in plasma (By similarity). Potentially has more than two calcium-binding sites and might additionally bind calcium in a non-specific manner (By similarity). The shared binding site between zinc and calcium at residue Asp-273 suggests a crosstalk between zinc and calcium transport in the blood (By similarity). The rank order of affinity is zinc > calcium > magnesium (By similarity). Binds to the bacterial siderophore enterobactin and inhibits enterobactin-mediated iron uptake of E.coli from ferric transferrin, and may thereby limit the utilization of iron and growth of enteric bacteria such as E.coli (PubMed:6234017). Does not prevent iron uptake by the bacterial siderophore aerobactin (PubMed:6234017)
Disease associations
Hyperthyroxinemia, familial dysalbuminemicFDAH
A disorder characterized by abnormally elevated levels of total serum thyroxine (T4) in euthyroid patients. It is due to abnormal serum albumin that binds T4 with enhanced affinity.
AnalbuminemiaANALBA
A rare autosomal recessive disorder manifested by the presence of a very low amount of circulating serum albumin. Affected individuals manifest mild edema, hypotension, fatigue, and, occasionally, lower body lipodystrophy (mainly in adult females). The most common biochemical finding is hyperlipidemia, with a significant increase in the total and LDL cholesterol concentrations, but normal concentrations of HDL cholesterol and triglycerides.
Sources
Last updated 5/8/2026, 6:34:39 AM