Hemopexin family
Encyclopedia
The hemopexin family is a family of evolutionarily related proteins
. Hemopexin-like repeats occur in vitronectin
and some matrix metalloproteinase
s family (matrixins). The HX repeats of some matrixins bind tissue inhibitor of metallopeptidases (TIMPs
).
Hemopexin is a serum glycoprotein that binds haem and transports it to the liver for breakdown and iron recovery, after which the free hemopexin returns to the circulation. Hemopexin prevents haem-mediated oxidative stress. Structurally hemopexin consists of two similar halves of approximately two hundred amino acid residues connected by a histidine-rich hinge region. Each half is itself formed by the repetition of a basic unit of some 35 to 45 residues. Hemopexin-like domains have been found in two other types of proteins, vitronectin, a cell adhesion and spreading factor found in plasma and tissues, and matrixins MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, MMP-11, MMP-12, MMP-14, MMP-15 and MMP-16, members of the matrix metalloproteinase family that cleave extracellular matrix constituents. These zinc endopeptidases, which belong to MEROPS peptidase subfamily M10A, have a single hemopexin-like domain in their C-terminal section. It is suggested that the hemopexin domain facilitates binding to a variety of molecules and proteins, for example the HX repeats of some matrixins bind tissue inhibitor of metallopeptidases (TIMPs).
Protein family
A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....
. Hemopexin-like repeats occur in vitronectin
Vitronectin
Vitronectin also known as VTN is a protein that in humans is encoded by the VTN gene.The protein encoded by this gene is a member of the pexin family...
and some matrix metalloproteinase
Matrix metalloproteinase
Matrix metalloproteinases are zinc-dependent endopeptidases; other family members are adamalysins, serralysins, and astacins. The MMPs belong to a larger family of proteases known as the metzincin superfamily....
s family (matrixins). The HX repeats of some matrixins bind tissue inhibitor of metallopeptidases (TIMPs
Tissue inhibitor of metalloproteinases
The matrix metalloproteinases are inhibited by specific endogenous tissue inhibitors of metalloproteinases , which comprise a family of four protease inhibitors: TIMP1, TIMP2, TIMP3 and TIMP4....
).
Hemopexin is a serum glycoprotein that binds haem and transports it to the liver for breakdown and iron recovery, after which the free hemopexin returns to the circulation. Hemopexin prevents haem-mediated oxidative stress. Structurally hemopexin consists of two similar halves of approximately two hundred amino acid residues connected by a histidine-rich hinge region. Each half is itself formed by the repetition of a basic unit of some 35 to 45 residues. Hemopexin-like domains have been found in two other types of proteins, vitronectin, a cell adhesion and spreading factor found in plasma and tissues, and matrixins MMP-1, MMP-2, MMP-3, MMP-9, MMP-10, MMP-11, MMP-12, MMP-14, MMP-15 and MMP-16, members of the matrix metalloproteinase family that cleave extracellular matrix constituents. These zinc endopeptidases, which belong to MEROPS peptidase subfamily M10A, have a single hemopexin-like domain in their C-terminal section. It is suggested that the hemopexin domain facilitates binding to a variety of molecules and proteins, for example the HX repeats of some matrixins bind tissue inhibitor of metallopeptidases (TIMPs).
Examples
Human gene encoding proteins containing hemopexin-like repeats include:- HPX (hemopexin, the founding member of this protein family)
- matrix metalloproteinases: MMP1MMP1Interstitial collagenase also known as matrix metalloproteinase-1 and fibroblast collagenase is an enzyme that in humans is encoded by the MMP1 gene.- Function :...
, MMP2MMP272 kDa type IV collagenase also known as matrix metalloproteinase-2 and gelatinase A is an enzyme that in humans is encoded by the MMP2 gene....
, MMP3MMP3Stromelysin-1 also known as matrix metalloproteinase-3 is an enzyme that in humans is encoded by the MMP3 gene. The MMP3 gene is part of a cluster of MMP genes which localize to chromosome 11q22.3.- Function :...
, MMP8MMP8Neutrophil collagenase, also known as matrix metalloproteinase-8 or PMNL collagenase , is a collagen cleaving enzyme which is present in the connective tissue of most mammals...
, MMP9MMP9Matrix metallopeptidase 9 , also known as 92 kDa type IV collagenase, 92 kDa gelatinase or gelatinase B , is an enzyme that in humans is encoded by the MMP9 gene.- Function :...
, MMP10MMP10Stromelysin-2 also known as matrix metalloproteinase-10 or transin-2 is an enzyme that in humans is encoded by the MMP10 gene.- Function :...
, MMP11MMP11Stromelysin-3 also known as matrix metalloproteinase-11 is am enzyme that in humans is encoded by the MMP11 gene.- Function :...
, MMP12Matrix metallopeptidase 12Matrix metalloproteinase-12 also known as macrophage metalloelastase or macrophage elastase is an enzyme that in humans is encoded by the MMP12 gene.- Function :...
, MMP13Matrix metallopeptidase 13Collagenase 3 is an enzyme that in humans is encoded by the MMP13 gene. It is a member of the matrix metalloproteinase family. Like most MMPs it secreated as an inactive pro-form. It is activated once the pro-domain is cleaved, leaving an active enzyme composed of the catalytic domain and the...
, MMP14MMP14Matrix metalloproteinase-14 is an enzyme that in humans is encoded by the MMP14 gene.Proteins of the matrix metalloproteinase family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well...
, MMP15MMP15Matrix metallopeptidase 15 also known as MMP15 is an enzyme that in humans is encoded by the MMP15 gene.- Function :Proteins of the matrix metalloproteinase family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction,...
, MMP16MMP16Matrix metalloproteinase-16 is an enzyme that in humans is encoded by the MMP16 gene.-External Links:* The MEROPS online database for peptidases and their inhibitors:...
, MMP17MMP17Matrix metalloproteinase-17 also known as membrane-type matrix metalloproteinase 4 is an enzyme that in humans is encoded by the MMP17 gene.- Function :...
, MMP19MMP19Matrix metalloproteinase-19 also known as matrix metalloproteinase RASI is an enzyme that in humans is encoded by the MMP19 gene.- Function :...
, MMP20MMP20Matrix metalloproteinase-20 also known as enamel metalloproteinase or enamelysin is an enzyme that in humans is encoded by the MMP20 gene.- Function :...
, MMP21MMP21Matrix metalloproteinase-21 is an enzyme that in humans is encoded by the MMP21 gene.- Function :This gene encodes a member of the matrix metalloproteinase family...
, MMP24MMP24Matrix metalloproteinase-24 is an enzyme that in humans is encoded by the MMP24 gene.-Further reading:...
, MMP25MMP25Matrix metalloproteinase-25 is an enzyme that in humans is encoded by the MMP25 gene.-External Links:* The MEROPS online database for peptidases and their inhibitors:...
, MMP27MMP27Matrix metallopeptidase 27 also known as MMP27 is a enzyme which in humans is encoded by the MMP27 gene.- Function :Proteins of the matrix metalloproteinase family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction,...
, MMP28MMP28Matrix metalloproteinase 28 also known as epilysin is an enzyme that in humans is encoded by the MMP28 gene.- Function :Proteins of the matrix metalloproteinase family are involved in the breakdown of extracellular matrix for both normal physiological processes, such as embryonic development,...
, - PRG4PRG4Proteoglycan 4 or lubricin is a protein that in humans is encoded by the PRG4 gene. This protein acts as a joint/intimal cell lubricant.- Function :...
(proteoglycan 4), and - VTNVitronectinVitronectin also known as VTN is a protein that in humans is encoded by the VTN gene.The protein encoded by this gene is a member of the pexin family...
(vitronectin).