Binding of substrate at the effector site of pyrophosphatase increases the rate of its hydrolysis at the active site

  title={Binding of substrate at the effector site of pyrophosphatase increases the rate of its hydrolysis at the active site},
  author={Tatyana S Sitnik and Svetlana M. Avaeva},
  journal={Biochemistry (Moscow)},
It is shown that in addition to the active site, each subunit of Escherichia coli inorganic pyrophosphatase (E-PPase) contains an extra binding site for the substrate magnesium pyrophosphate or its non-hydrolyzable analog magnesium methylenediphosphonate. The occupancy of the extra site stimulates the substrate conversion. Binding affinity of this site decreased or disappeared upon the conversion of E-PPase into a trimeric form or introduction of point mutations. However, when the slowly… 

Crystal Structure of Inorganic Pyrophosphatase From Schistosoma japonicum Reveals the Mechanism of Chemicals and Substrate Inhibition

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Analysis of data confirms the proposed location of an effector binding site in a cluster of positively charged amino acid residues including the side chains of Arg43, Lys146, Lys112, and Lys115 (subunit B) and plays a key role in forming contacts with the phosphate groups of the three studied effectors.