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Phosphoenol transphosphorylase
7.Transferring phosphorus-containing groups
1.Phosphotransferases with an alcohol group as acceptor
ADP
+ phosphoenolpyruvateUTP
GTP
CTP
ITP
dATP
pyruvate
hydroxylamina
Fluorida
UDP
GDP
CDP
IDP
dADP
phosphoenolpyruvate
O-phosphorilhydroxylamine
TP, GTP, CTP, ITP and dATP can also act as donors. Also phosphorylates hydroxylamine and fluoride in the presence of CO2.
PK requires both magnesium and potassium ions for its activity. PK is found in all living organisms. In vertebrates there are four, tissues specific, isozymes: L (liver), R (red cells), M1 (muscle, heart, and brain), and M2 (early fetal tissues). In Escherichia coli there are two isozymes: PK-I and PK-II. All PK isozymes seem to be tetramers of identical subunits of about 500 amino acid residues.
As a signature pattern for PK it has been selected a conserved region that includes a
lysine residue which seems to be the acid/base catalyst responsible for the
interconversion of pyruvate and enolpyruvate, and a glutamic acid residue
implicated in the binding of the magnesium ion.
Reference