Design, synthesis, and biochemical evaluation of phosphonate and phosphonamidate analogs of glutathionylspermidine as inhibitors of glutathionylspermidine synthetase/amidase from Escherichia coli.
Three phosphapeptides designed to mimic two distinct tetrahedral intermediates formed during either the synthesis or hydrolysis of glutathionylspermidine (Gsp) were synthesized and evaluated as inhibitors of the bifunctional enzyme Gsp synthetase/amidase. While the polyamine-containing phosphapeptides were determined to be potent and selective inhibitors, they selectively inhibit the synthetase activity over the amidase domain. A phosphonate-containing tetrahedral mimic is a reversible mixed-type inhibitor of Gsp synthetase with an inhibition constant of 6 microM for the inhibitor binding to the free enzyme (Ki) and 14 microM for the inhibitor binding to the enzyme-substrate complex (Ki'). The corresponding phosphonamidate is a slow-binding inhibitor with a Ki of 24 microM and a Ki* (isomerization inhibition constant) of 0.88 microM. A non-polyamine-containing phosphonamidate exhibits no significant inhibition of the synthetase or amidase activity.
Chen
S
S
Interdepartmental Program in Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor 48109-1055, USA.
Lin
C H
CH
Kwon
D S
DS
Walsh
C T
CT
Coward
J K
JK
D019732:Amide Synthases / Q000037:antagonists & inhibitors*; D001426:Bacterial Proteins / Q000378:metabolism; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology*; D004926:Escherichia coli / Q000201:enzymology*; D005978:Glutathione / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D007700:Kinetics; D063065:Organophosphonates / Q000138:chemical synthesis / Q000494:pharmacology; D010748:Phosphopeptides / Q000138:chemical synthesis* / Q000494:pharmacology*; D013095:Spermidine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D063065:Organophosphonates; D010748:Phosphopeptides; C012333:glutathionylspermidine; D019732:Amide Synthases; C081536:glutathionylspermidine synthetase; D005978:Glutathione; D013095:Spermidine