PROSITE documentation PDOC00066
Malate dehydrogenase active site signature


Malate dehydrogenase (EC (MDH) [1,2] catalyzes the interconversion of malate to oxaloacetate utilizing the NAD/NADH cofactor system. The enzyme participates in the citric acid cycle and exists in all aerobics organisms.

While prokaryotic organisms contains a single form of MDH, in eukaryotic cells there are two isozymes: one which is located in the mitochondrial matrix and the other in the cytoplasm. Fungi and plants also harbor a glyoxysomal form which functions in the glyoxylate pathway. In plants chloroplast there is an additional NADP-dependent form of MDH (EC which is essential for both the universal C3 photosynthesis (Calvin) cycle and the more specialized C4 cycle.

As a signature pattern for this enzyme we have chosen a region that includes two residues involved in the catalytic mechanism [3]: an aspartic acid which is involved in a proton relay mechanism, and an arginine which binds the substrate.


MDH from archaebacteria do not belong to the above family; they are evolutionary related to lactate dehydrogenases [4].

Last update:

November 1995 / Text revised.


Technical section

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

MDH, PS00068; Malate dehydrogenase active site signature  (PATTERN)


1AuthorsMcAlister-Henn L.
SourceTrends Biochem. Sci. 13:178-181(1988).

2AuthorsGietl C.
TitleMalate dehydrogenase isoenzymes: cellular locations and role in the flow of metabolites between the cytoplasm and cell organelles.
SourceBiochim. Biophys. Acta 1100:217-234(1992).
PubMed ID1610875

3AuthorsBirktoft J.J. Rhodes G. Banaszak L.J.
TitleRefined crystal structure of cytoplasmic malate dehydrogenase at 2.5-A resolution.
SourceBiochemistry 28:6065-6081(1989).
PubMed ID2775751

4AuthorsCendrin F. Chroboczek J. Zaccai G. Eisenberg H. Mevarech M.
TitleCloning, sequencing, and expression in Escherichia coli of the gene coding for malate dehydrogenase of the extremely halophilic archaebacterium Haloarcula marismortui.
SourceBiochemistry 32:4308-4313(1993).
PubMed ID8476859

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