Tethered bisubstrate derivatives as probes for mechanism and as inhibitors of aminoglycoside 3'-phosphotransferases

J Org Chem. 2000 Nov 3;65(22):7422-31. doi: 10.1021/jo000589k.


Aminoglycoside 3'-phosphotransferases [APH(3')s] phosphorylate aminoglycoside antibiotics, a reaction that inactivates the antibiotics. These enzymes are the primary cause of resistance to aminoglycosides in bacteria. APH(3')-Ia operates by a random-equilibrium BiBi mechanism, whereas APH(3')-IIIa catalyzes its reaction by the Theorell-Chance mechanism, a form of ordered BiBi mechanism. Hence, both substrates have to be present in the active site prior to the transfer of phosphate by both mechanisms. Four bisubstrate analogues, compounds 1-4, were designed and synthesized as inhibitors for APH(3')s. These compounds are made of adenosine linked covalently to the 3'-hydroxyl of neamine (an aminoglycoside) via all-methylene tethers of 5-8 carbons. The K(i) values measured for these compounds indicated that affinities of APH(3')-Ia and APH(3')-IIa for compounds 2 and 3 (six- and seven-carbon tethers, respectively) were the best, and the inhibition constants for the two were comparable.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Carbohydrate Sequence
  • Enzyme Inhibitors / chemical synthesis*
  • Enzyme Inhibitors / chemistry
  • Kanamycin Kinase / antagonists & inhibitors*
  • Kanamycin Kinase / chemistry*
  • Kinetics
  • Models, Molecular
  • Molecular Sequence Data
  • Substrate Specificity


  • Enzyme Inhibitors
  • Kanamycin Kinase