A number of enzymes that catalyze the transfer of a phosphoryl group from
phosphoenolpyruvate (PEP) via a phospho-histidine intermediate have been shown
to be structurally related [1,2,3,4]. These enzymes are:
Pyruvate,orthophosphate dikinase (EC 18.104.22.168) (PPDK). PPDK catalyzes the
reversible phosphorylation of pyruvate and phosphate by ATP to PEP and
diphosphate. In plants PPDK function in the direction of the formation of
PEP, which is the primary acceptor of carbon dioxide in C4 and crassulacean
acid metabolism plants. In some bacteria, such as Bacteroides symbiosus,
PPDK functions in the direction of ATP synthesis.
Phosphoenolpyruvate synthase (EC 22.214.171.124) (pyruvate,water dikinase). This
enzyme catalyzes the reversible phosphorylation of pyruvate by ATP to form
PEP, AMP and phosphate, an essential step in gluconeogenesis when pyruvate
and lactate are used as a carbon source.
Phosphoenolpyruvate-protein phosphatase (EC 126.96.36.199). This is the first
enzyme of the phosphoenolpyruvate-dependent sugar phosphotransferase system
(PTS), a major carbohydrate transport system in bacteria. The PTS catalyzes
the phosphorylation of incoming sugar substrates concomitant with their
translocation across the cell membrane. The general mechanism of the PTS is
the following: a phosphoryl group from PEP is transferred to enzyme-I (EI)
of PTS which in turn transfers it to a phosphoryl carrier protein (HPr).
Phospho-HPr then transfers the phosphoryl group to a sugar-specific
All these enzymes share the same catalytic mechanism: they bind PEP and
transfer the phosphoryl group from it to a histidine residue. The sequence
around that residue is highly conserved and can be used as a signature pattern
for these enzymes. As a second signature pattern we selected a conserved
region in the C-terminal part of the PEP-utilizing enzymes. The biological
significance of this region is not yet known.
December 2004 / Pattern and text revised.
PROSITE methods (with tools and information) covered by this documentation:
Reizer J. Hoischen C. Reizer A. Pham T.N. Saier M.H. Jr.
Sequence analyses and evolutionary relationships among the energy-coupling proteins Enzyme I and HPr of the bacterial phosphoenolpyruvate: sugar phosphotransferase system.
Pocalyko D.J. Carroll L.J. Martin B.M. Babbitt P.C. Dunaway-Mariano D.
Analysis of sequence homologies in plant and bacterial pyruvate phosphate dikinase, enzyme I of the bacterial phosphoenolpyruvate: sugar phosphotransferase system and other PEP-utilizing enzymes. Identification of potential catalytic and regulatory motifs.
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