IgA specific serine endopeptidase

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IgA-specific serine endopeptidase
EC number3.4.21.72
CAS number55127-02-1
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum

IgA protease (EC, IgA-specific serine endopeptidase, IgA proteinase, IgA-specific proteinase, immunoglobulin A protease, immunoglobulin A proteinase) is an enzyme.[1][2] This enzyme catalyses the following chemical reaction

Cleavage of immunoglobulin A molecules at certain Pro- bonds in the hinge region. No small molecule substrates are known

This enzyme is secreted by Gram-negative bacteria Neisseria gonorrhoeae, Neisseria meningitidis, Haemophilus influenzae, and Gram-positive Streptococcus pneumoniae.

The action of IgA protease allows the above mentioned bacteria to adhere to mucous membranes.

An IgA protease is a highly specific 106kDa enzyme that cleaves amino acid sequences of certain proteins. The natural substrate of IgA proteases is immunoglobulin A, hence its name. The enzyme is in fact capable of cleavage of proteins with the amino acid sequence Cleaves N-X-Z-Pro-Pro/-Y-Pro-C, where the X in the squence preferably is a Proline or Serine; the Y = Threonine, Serine or Alanine; and Z preferably is Arginine or Threonine. Because of the sequence that the enzyme is able to cleave, it is also called IgAse Pro-Pro-Y-Pro. Thus, the IgA protease act by cleaving the proline-rich hinge region of the heavy chain of IgA1. Three major bacteria, Neisseria gonorrhœae (which causes gonorrhea), Streptococcus pneumoniae, and Haemophilus influenzae type B, release the IgA protease which destroys IgA.[3]

See also[edit]


  1. ^ Plaut AG (1983). "The IgA1 proteases of pathogenic bacteria". Annual Review of Microbiology. 37 (1): 603–22. doi:10.1146/annurev.mi.37.100183.003131. PMID 6416146.
  2. ^ Bachovchin WW, Plaut AG, Flentke GR, Lynch M, Kettner CA (March 1990). "Inhibition of IgA1 proteinases from Neisseria gonorrhoeae and Hemophilus influenzae by peptide prolyl boronic acids". The Journal of Biological Chemistry. 265 (7): 3738–43. PMID 2105953.
  3. ^ Qiu J, Brackee GP, Plaut AG (March 1996). "Analysis of the specificity of bacterial immunoglobulin A (IgA) proteases by a comparative study of ape serum IgAs as substrates". Infection and Immunity. 64 (3): 933–7. PMC 173859. PMID 8641803.

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