# Mechanism of Slow Onset Enzyme Inhibition and Translation to Time-Dependent Drug Activity

> **NIH NIH R35** · STATE UNIVERSITY NEW YORK STONY BROOK · 2024 · $392,024

## Abstract

Many drug candidates fail in clinical trials due to lack of efficacy or insufficient safety. We
speculate that our poor success rate at predicting in vivo drug efficacy stems from a reliance on
in vitro assessments of drug activity that are performed at constant drug concentration (under
equilibrium conditions), when in fact drug concentration is not constant in the human body. We
thus propose that the kinetics of drug-target complex formation and breakdown is a critical factor
in modulating drug action. In this proposal we will elucidate the molecular factors that dictate the
impact of drug-target residence time on in vivo drug activity. These studies will focus on inhibitors
of three antibacterial targets: UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase
(LpxC), acetyl-CoA carboxylase (ACC) and leucyl-tRNA synthetase (LeuRS). We will quantify
the role that intracellular events such as target (re)synthesis, target degradation and target
vulnerability have on the correlation between drug-target residence time and antibacterial activity
determined as a function of drug concentration. This includes the prolongation of antibacterial
activity following removal of drug from the system (the post-antibiotic effect). We will develop
structure-kinetics relationships for time-dependent enzyme inhibition using a combination of
structural and computational biology coupled with enzyme kinetics and synthesize inhibitors with
extended target engagement. A mathematical model will be used that links drug-target kinetics
and drug pharmacokinetics with predictions of antibacterial activity in whole cells and animal
models of infection. Improved ability to predict in vivo drug action from in vitro parameters will
have a dramatic impact on the discovery of new therapeutic agents.

## Key facts

- **NIH application ID:** 10909811
- **Project number:** 5R35GM149297-02
- **Recipient organization:** STATE UNIVERSITY NEW YORK STONY BROOK
- **Principal Investigator:** PETER J TONGE
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $392,024
- **Award type:** 5
- **Project period:** 2023-09-01 → 2028-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10909811

## Citation

> US National Institutes of Health, RePORTER application 10909811, Mechanism of Slow Onset Enzyme Inhibition and Translation to Time-Dependent Drug Activity (5R35GM149297-02). Retrieved via AI Analytics 2026-05-31 from https://api.ai-analytics.org/grant/nih/10909811. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*