Enzyme Aptamer Screening Service

Date：2026-01-14

Enzyme Aptamer Screening Service is a specialized contract research service where providers employ SELEX (Systematic Evolution of Ligands by EXponential Enrichment) to discover aptamers that bind with high specificity and affinity to a target enzyme. These aptamers can be designed not only to bind but also to modulate the enzyme’s activity (inhibit or activate), making them powerful tools for therapeutics, diagnostics, and biochemical research.

Key Differentiators from Antibody Screening:

Functional Screening: A major goal is often to identify inhibitory or activating aptamers. Therefore, the screening process may incorporate activity-based selection or functional assays early on.
Target Site Complexity: The target can be the entire enzyme, its active site, an allosteric site, or a specific conformational state (e.g., open vs. closed).
Conformational Sensitivity: Enzymes are dynamic. Aptamers can be selected to recognize a specific functional conformation, which is a unique advantage.

Typical Screening Workflow:

1. Project Design & Target Preparation:

Define Objective: Is the goal pure detection, potent inhibition, allosteric modulation, or capturing a specific enzyme form?
Enzyme Quality: Requires a highly pure, functional, and correctly folded enzyme. Activity assays confirm functionality.
Selection Strategy: Choice of Toggle SELEX (for broad species cross-reactivity), Capture SELEX, or innovative methods like ExSELEX (for complex biological fluids).

2. The SELEX Process with a Functional Focus:

Binding & Stringency: Standard incubation, washing, and elution cycles are performed.
Functional Partitioning (Optional but powerful): To directly enrich for inhibitors, the library may be incubated with the enzyme before adding its substrate. Sequences that prevent the enzyme-substrate interaction are retained.
Counter-Selections: Against related enzyme isoforms, substrates, or co-factors to ensure high specificity.

3. High-Throughput Analysis & Characterization:

Sequencing & Bioinformatics: NGS identifies enriched families. Clustering analysis finds consensus motifs.
Rapid Functional Screening: Individual candidate aptamers are synthesized and tested in high-throughput enzyme activity assays (e.g., colorimetric/fluorimetric microplate assays) to quickly pinpoint leads with the desired inhibitory or activating effect.
In-Depth Biophysical Analysis:
- Affinity (Kd): Measured via SPR or BLI.
- Potency (IC50/EC50): For inhibitors/activators, determined from dose-response curves in activity assays.
- Mechanism of Action: Studies (e.g., kinetic assays) to determine if inhibition is competitive, non-competitive, or allosteric.

4. Delivery & Optimization:

Delivery of lead functional aptamer sequences and characterization data.
Optimization Services: Truncation to find the minimal active sequence, site-specific modification (e.g., for stability in serum), and conjugation to reporters or polymers.

Key Applications of Enzyme Aptamers:

Therapeutic Inhibitors: As alternatives to small-molecule drugs or antibodies for targeting disease-driving enzymes (e.g., proteases, kinases).
Biosensors (Aptasensors): For detecting enzyme activity or its presence as a biomarker in diagnostics.
Research Tools: To selectively inhibit or track specific enzymes in complex pathways without the genetic manipulation needed for knockouts.
Industrial & Analytical Use: In biocatalysis control or as components in detection kits.

Critical Factors for Service Selection:

Proven Success with Enzymes: Ask for case studies showing generated aptamers with measured inhibitory (IC50) or activating effects.
Functional Assay Integration: The provider should have robust, miniaturized enzyme activity assays to integrate into the screening pipeline.
Understanding of Enzyme Kinetics: Expertise in designing selections that consider enzyme mechanics (e.g., avoiding mere substrate mimics).
Protein Production & QC: Ability to handle and maintain active enzymes throughout the lengthy SELEX process.