Harnessing Contact-Quenched, Profluorescent Chemical Probes for Sensitive Determination and High-Throughput Measurements of Enzyme Activity
Bibliographic record
Abstract
High Resolution Image Download MS PowerPoint Slide Dual-labeled, profluorescent chemical probes have been developed to quantify and visualize a specific enzyme’s activity in complex biological media. The intact chemical probes often exhibit minimal fluorescence due to fluorescence quenching, but their intrinsic fluorescence can be released by a favorable enzyme-catalyzed reaction. Contact quenching represents one of several fluorescence quenching mechanisms. However, it is seldom intentionally implemented in the synthesis of dual-labeled, profluorescent chemical probes, because the structure of a contact quenching construct requires the formation of a ground-state fluorophore-quencher/-fluorophore complex. The ability of such dual-labeled molecular probes to act as intramolecular dimers cannot be predicted. We previously revealed that a mono exo -bicyclo[6.1.0]nonyne ( exo -BCN)-derivatized cystamine framework was critical to synthesizing sensitive, dual-labeled, profluorescent chemical probes capable of contact quenching. Here, we exploited the nonsymmetrical mono - exo -BCN-cystamine backbone by sequentially coupling it with two different carboxyfluorescein (FAM) derivatives and subsequently synthesizing four nonsymmetrical bis -FAM chemical probes. The fluorescence turn-on properties of the bis -FAM chemical probe with the lowest background FAM fluorescence were characterized by kinetic studies. Moreover, the release of two FAM equivalents from the fluorescence turn-on chemical probe during reactions was utilized to develop sensitive assays for measuring the activity and inhibition of two serum biomarkers, butyrylcholinesterase (BChE) and paraoxonase 1 (PON1) lactonase. We also developed an efficient, high-throughput assay for detecting BChE activity based on the chemical probe. Finally, the fluorescence assays successfully quantified the activities of BChE and PON1 lactonase in human serum.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".