A BODIPY-Tagged Phosphono Peptide as Activity-Based Probe for Human Leukocyte Elastase

Area of Science:

• Biochemistry
• Chemical Biology
• Enzyme Inhibitors

Background:

• Human leukocyte elastase is implicated in numerous inflammatory conditions.
• Targeting human leukocyte elastase is crucial for understanding and treating inflammatory disorders.
• Development of specific probes is essential for studying enzyme activity and inhibition.

Purpose of the Study:

• To design and synthesize a novel activity-based fluorescent probe for human leukocyte elastase.
• To characterize the probe's inhibitory activity and selectivity.
• To demonstrate the probe's utility in detecting human leukocyte elastase.

Main Methods:

• Design and synthesis of a peptidic phosphonate-based probe incorporating a BODIPY fluorophore and a clickable moiety.
• Utilizing copper-catalyzed alkyne-azide 1,3-dipolar cycloaddition for probe assembly.
• Assessing probe activity via second-order rate constant determination and in-gel fluorescence analysis.
• Evaluating probe selectivity against related proteases.

Main Results:

• The synthesized probe (compound 6) functions as an active site-directed inhibitor of human leukocyte elastase.
• The probe exhibits a high second-order rate constant for inactivation (88400 M⁻¹s⁻¹).
• In-gel fluorescence analysis confirmed the probe's suitability for detecting human leukocyte elastase.
• Labeling experiments and inhibition assays demonstrated high selectivity for human leukocyte elastase over other proteases.

Conclusions:

• The novel peptidic phosphonate probe is a potent and selective inhibitor of human leukocyte elastase.
• The probe's fluorescent properties enable effective detection and monitoring of enzyme activity.
• This tool holds promise for advancing biomedical studies of inflammatory disorders involving human leukocyte elastase.