PROSITE documentation PDOC00618
Aminotransferases class-IV signature


Aminotransferases share certain mechanistic features with other pyridoxal-phosphate dependent enzymes, such as the covalent binding of the pyridoxal-phosphate group to a lysine residue. On the basis of sequence similarity, these various enzymes can be grouped [1,2] into subfamilies. One of these, called class-IV, currently consists of the following enzymes:

  • Branched-chain amino-acid aminotransferase (EC (transaminase B), a bacterial (gene ilvE) and eukaryotic enzyme which catalyzes the reversible transfer of an amino group from 4-methyl-2-oxopentanoate to glutamate, to form leucine and 2-oxoglutarate.
  • D-alanine aminotransferase (EC A bacterial enzyme which catalyzes the transfer of the amino group from D-alanine (and other D-amino acids) to 2-oxoglutarate, to form pyruvate and D-aspartate.
  • 4-amino-4-deoxychorismate (ADC) lyase (gene pabC). A bacterial enzyme that converts ADC into 4-aminobenzoate (PABA) and pyruvate.

The above enzymes are proteins of about 270 to 415 amino-acid residues that share a few regions of sequence similarity. Surprisingly, the best conserved region does not include the lysine residue to which the pyridoxal-phosphate group is known to be attached, in ilvE. The region we use as a signature pattern is located some 40 residues at the C-terminus side of the PlP-lysine.

Last update:

December 2001 / Pattern and text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

AA_TRANSFER_CLASS_4, PS00770; Aminotransferases class-IV signature  (PATTERN)


1AuthorsGreen J.M. Merkel W.K. Nichols B.P.
TitleCharacterization and sequence of Escherichia coli pabC, the gene encoding aminodeoxychorismate lyase, a pyridoxal phosphate-containing enzyme.
SourceJ. Bacteriol. 174:5317-5323(1992).
PubMed ID1644759

2AuthorsBairoch A.
SourceUnpublished observations (1992).

PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)