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Effect of bivalent cations on the interaction of transketolase with its donor substrate
Author(s) -
Sevostyanova Irina A.,
Yurshev Vladimir A.,
Solovjeva Olga N.,
Zabrodskaya Svetlana V.,
Kochetov German A.
Publication year - 2008
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.21880
Subject(s) - transketolase , chemistry , affinities , bivalent (engine) , enzyme , substrate (aquarium) , stereochemistry , cofactor , active site , magnesium , phosphate , binding site , biochemistry , metal , biology , organic chemistry , ecology
The effect of the type of the cation cofactor of transketolase (i.e., Ca 2+ or Mg 2+ ) on its interaction with xylulose 5‐phosphate (donor substrate) has been studied. In the presence of magnesium, the active centers of the enzyme were functionally equivalent with respect to xylulose 5‐phosphate binding and exhibited identical affinities for the donor substrate. Substitution of Ca 2+ for Mg 2+ results in the loss of the equivalence. In particular, this becomes apparent on binding of xylulose 5‐phosphates to one of the two active centers of the enzyme, which caused the second center to undergo a several fold decrease in the affinity for the donor substrate. Proteins 2008. © 2008 Wiley‐Liss, Inc.