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Matrix metallopeptidase 20
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols MMP20 ; AI2A2; MMP-20
External IDs OMIM604629 MGI1353466 HomoloGene21001 IUPHAR: 1643 GeneCards: MMP20 Gene
EC number 3.4.24.-
RNA expression pattern
PBB GE MMP20 207599 at tn.png
More reference expression data
Species Human Mouse
Entrez 9313 30800
Ensembl ENSG00000137674 ENSMUSG00000018620
UniProt O60882 P57748
RefSeq (mRNA) NM_004771 NM_013903
RefSeq (protein) NP_004762 NP_038931
Location (UCSC) Chr 11:
102.45 – 102.5 Mb
Chr 9:
7.63 – 7.67 Mb
PubMed search [1] [2]

Matrix metalloproteinase-20 (MMP-20) also known as enamel metalloproteinase or enamelysin is an enzyme that in humans is encoded by the MMP20 gene.[1][2]


Proteins of the matrix metalloproteinase (MMP) family are involved in the breakdown of extracellular matrix in normal physiological processes, such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes, such as arthritis and metastasis. Most MMP's are secreted as inactive proproteins which are activated when cleaved by extracellular proteinases.

MMP-20, also known as enamelysin, appears to be the only MMP that is tooth-specific and it is expressed by cells of different developmental origin (i.e. epithelial ameloblasts and mesenchymal odontoblasts).

Clinical significance[edit]

The human MMP-20 gene contains 10 exons and is part of a cluster of matrix metalloproteinase genes that localize to human chromosome 11q22.3.[2] A mutation in this gene, which alters the normal splice pattern and results in premature termination of the encoded protein, has been associated with amelogenesis imperfecta. Enamel in the absence of MMP-20 is hypoplastic (thin), contains less mineral (only one-third as much total mineral as wild type), and contains more protein and water. In general, MMP-20 functions in enamel are to cleave enamel matrix proteins at specific cleavage sites.[3]


  1. ^ Llano E, Pendas AM, Knauper V, Sorsa T, Salo T, Salido E, Murphy G, Simmer JP, Bartlett JD, Lopez-Otin C (Jan 1998). "Identification and structural and functional characterization of human enamelysin (MMP-20)". Biochemistry 36 (49): 15101–15108. doi:10.1021/bi972120y. PMID 9398237. 
  2. ^ a b "Entrez Gene: MMP20 matrix metallopeptidase 20 (enamelysin)". 
  3. ^ Moradian-Oldak J (2012). "Protein-mediated enamel mineralization". Front. Biosci. 17: 1996–2023. doi:10.2741/4034. PMC 3442115. PMID 22652761. 

Further reading[edit]

External links[edit]

  • The MEROPS online database for peptidases and their inhibitors: M10.019