Tartrate-resistant acid phosphatase

ACP5
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	2BQ8, 1WAR
Identifiers
Aliases	ACP5, HPAP, SPENCDI, TRAP, TRACP5a, TRACP5b, TrATPase, acid phosphatase 5, tartrate resistant, TRAcP
External IDs	OMIM: 171640; MGI: 87883; HomoloGene: 115578; GeneCards: ACP5; OMA:ACP5 - orthologs
Gene location (Human)
Chr.	Chromosome 19 (human)
End	11,579,993 bp
Gene location (Mouse)
Chr.	Chromosome 9 (mouse)
End	22,047,007 bp
RNA expression pattern
	Top expressed in
	periodontal fiber; ; upper lobe of left lung; ; right lung; ; lower lobe of lung; ; tibia; ; granulocyte; ; lymph node; ; spleen; ; rectum; ; appendix;
	Top expressed in
	body of femur; ; tibiofemoral joint; ; white adipose tissue; ; subcutaneous adipose tissue; ; fetal liver hematopoietic progenitor cell; ; brown adipose tissue; ; spleen; ; intercostal muscle; ; tunica adventitia of aorta; ; large intestine;
	More reference expression data
	More reference expression data
Gene ontology
Molecular function	ferric iron binding; acid phosphatase activity; metal ion binding; ferrous iron binding; hydrolase activity;
Cellular component	integral component of membrane; cytosol; lysosome;
Biological process	riboflavin metabolic process; dephosphorylation; response to lipopolysaccharide; negative regulation of interleukin-1 beta production; negative regulation of interleukin-12 production; negative regulation of tumor necrosis factor production; negative regulation of superoxide anion generation; response to cytokine; negative regulation of nitric oxide biosynthetic process; bone resorption; negative regulation of inflammatory response; defense response to Gram-positive bacterium; bone morphogenesis; ossification;
	Sources:Amigo / QuickGO
Orthologs
	54
	11433
	ENSG00000102575
	ENSMUSG00000001348
	P13686
	Q05117
	NM_001111034; NM_001111035; NM_001111036; NM_001611; NM_001322023
	NM_001102404; NM_001102405; NM_007388
	NP_001104504; NP_001104505; NP_001104506; NP_001308952; NP_001602
	NP_001095874; NP_001095875; NP_031414
	Wikidata
View/Edit Human	View/Edit Mouse

Tartrate-resistant acid phosphatase (TRAP or TRAPase), also called acid phosphatase 5, tartrate resistant (ACP5) or TRAP5b, is a glycosylated monomeric metalloprotein enzyme expressed in mammals. It has a molecular weight of approximately 35kDa, a basic isoelectric point (7.6–9.5), and optimal activity in acidic conditions. TRAP is synthesized as latent proenzyme and activated by proteolytic cleavage and reduction. It is differentiated from other mammalian acid phosphatases by its resistance to inhibition by tartrate and by its molecular weight.

The mechanism of phosphate ester hydrolysis by TRAP is through a nucleophilic attack mechanism, whereby, catalysis occurs with the binding of a phosphate-substrate to the Fe²⁺ in the active site of TRAP. This is then followed by a nucleophilic attack by a hydroxide ligand on the bound phosphorus atom, resulting in cleavage of the phosphate ester bond and production of an alcohol. The exact identity and mechanism of the hydroxide ligand is unclear, but it is thought to be either a hydroxide that bridges the metal ions within the active site or a terminal hydroxide bound to Fe³⁺, with conflicting reports for both mechanisms.