Metalloproteinases constitute a family of enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

s from the group of protease

Protease

A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain forming the protein....

s, classified by the nature of the most prominent functional group

Functional group

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...

 in their active site

Active site

In biology the active site is part of an enzyme where substrates bind and undergo a chemical reaction. The majority of enzymes are proteins but RNA enzymes called ribozymes also exist. The active site of an enzyme is usually found in a cleft or pocket that is lined by amino acid residues that...

. These are proteolytic

Proteolysis

Proteolysis is the directed degradation of proteins by cellular enzymes called proteases or by intramolecular digestion.-Purposes:Proteolysis is used by the cell for several purposes...

 enzymes whose catalytic mechanism involves a metal. Most metalloproteases are zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

-dependent, but some use cobalt

Cobalt

Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

. The metal ion is coordinated to the protein via three ligands. The ligands co-ordinating the metal ion can vary with histidine

Histidine

Histidine Histidine, an essential amino acid, has a positively charged imidazole functional group. It is one of the 22 proteinogenic amino acids. Its codons are CAU and CAC. Histidine was first isolated by German physician Albrecht Kossel in 1896. Histidine is an essential amino acid in humans...

, glutamate, aspartate, lysine

Lysine

Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....

 and arginine

Arginine

Arginine is an α-amino acid. The L-form is one of the 20 most common natural amino acids. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that codify for arginine during...

. The fourth coordination position is taken up by a labile water molecule.

There are two subgroups of metalloproteinases:

• exopeptidase
  Exopeptidase
  An exopeptidase is an enzyme produced in the pancreas that catalyses the removal of an amino acid from the end of a polypeptide chain. Exopeptidase cleaves the end of a polypeptide chain....
  
  s: metalloexopeptidase
  Metalloexopeptidase
  A metalloexopeptidase is a type of enzyme which acts as a metalloproteinase exopeptidase.The term "metallocarboxypeptidase" is sometimes used to describe a metalloexopeptidase carboxypeptidase....
  
  s (EC number
  EC number
  The Enzyme Commission number is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze....
  
  : 3.4.17).
• endopeptidase
  Endopeptidase
  Endopeptidase or endoproteinase are proteolytic peptidases that break peptide bonds of nonterminal amino acids , in contrast to exopeptidases, which break peptide bonds from their end-pieces. For this reason, endopeptidases cannot break down peptides into monomers, while exopeptidases can break...
  
  s: metalloendopeptidase
  Metalloendopeptidase
  A metalloendopeptidase is an enzyme that functions as a metalloproteinase endopeptidase....
  
  s (3.4.24). Well known metalloendopeptidases include ADAM protein
  ADAM Protein
  ADAM is a family of peptidase proteins. It is also known as the adamalysin family or MDC family. ADAMs are classified as sheddases because they cut off or shed extracellular portions of transmembrane proteins. For example, ADAM10 can cut off part of the HER2 receptor, activating it...
  
  s and 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.

Treatment with chelating agents such as EDTA

EDTA

Ethylenediaminetetraacetic acid, widely abbreviated as EDTA , is a polyamino carboxylic acid and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand...

 leads to complete inactivation. EDTA is a metal chelator which removes zinc, which is essential for activity. They are also inhibited by the chelator orthophenanthroline.

External links

• The MEROPS
  Merops
  Merops may refer to:* Merops , a genus of bee-eaters.* MEROPS, an on-line database for peptidases.It may also refer to several figures from Greek mythology:* King of Ethiopia, husband of Clymene, who lay with Helios and bore Phaethon...
  
  online database for peptidases and their inhibitors: Metallo Peptidases
• Proteopedia: Metalloproteases