PROSITE documentation PDOC00145
Isocitrate lyase signature


Isocitrate lyase (EC [1,2] is an enzyme that catalyzes the conversion of isocitrate to succinate and glyoxylate. This is the first step in the glyoxylate bypass, an alternative to the tricarboxylic acid cycle in bacteria, fungi and plants.

A cysteine, a histidine and a glutamate or aspartate have been found to be important for the enzyme's catalytic activity. Only one cysteine residue is conserved between the sequences of the fungal, plant and bacterial enzymes; it is located in the middle of a conserved hexapeptide that can be used as a signature pattern for this type of enzyme.

ICL is evolutionary related to two other type of enzymes:

  • Carboxyphosphonoenolpyruvate phosphonomutase (EC (CPEP mutase). It forms a carbon-phosphorus bond in a rearrangement leading from carboxyphosphonoenolpyruvate (CPEP) to phosphinopyruvate.
  • Phosphoenolpyruvate phosphomutase (EC (PEP mutase) [3]. It forms a carbon-phosphorus bond by converting phosphoenolpyruvate (PEP) to phosphonopyruvate.
Last update:

May 2004 / Text revised.


Technical section

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

ISOCITRATE_LYASE, PS00161; Isocitrate lyase signature  (PATTERN)


1AuthorsBeeching J.R.
TitleHigh sequence conservation between isocitrate lyase from Escherichia coli and Ricinus communis.
SourceProtein Seq. Data Anal. 2:463-466(1989).
PubMed ID2696959

2AuthorsAtomi H. Ueda M. Hikida M. Hishida T. Teranishi Y. Tanaka A.
TitlePeroxisomal isocitrate lyase of the n-alkane-assimilating yeast Candida tropicalis: gene analysis and characterization.
SourceJ. Biochem. 107:262-266(1990).
PubMed ID2361956

3AuthorsHuang K. Li Z. Jia Y. Dunaway-Mariano D. Herzberg O.
TitleHelix swapping between two alpha/beta barrels: crystal structure of phosphoenolpyruvate mutase with bound Mg(2+)-oxalate.
SourceStructure 7:539-548(1999).
PubMed ID10378273

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