Multi-dimensional NMR Substrate Probe for Enzyme Activity Detection
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Solution Overview
Problem
Conventional methods for detecting enzyme activity, such as MRI probes, luminescent probes, and fluorescent probes, face challenges including low signal/noise ratio, poor biocompatibility, and difficulty in capturing signals from deep within the body due to low light permeability and scattering, as well as non-specificity and limited dosing, which hinder accurate monitoring of enzyme activity, especially for proteases like MMP.
Innovation Solution
A substrate probe with stable isotopes labeled at enzyme recognition sites, utilizing multiple NMR active nuclei with different resonance frequencies, allowing for high-sensitivity detection of enzyme activity through multi-dimensional nuclear magnetic resonance methods and imaging, enhancing biocompatibility and specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI probes are used to detect enzyme activity, then the detection can be performed non-invasively, but the signal/noise ratio is low and the degree of relaxation caused by enzymatic activation is relatively low
Solution Approach 1:
The invention uses a composite probe structure consisting of a substrate molecule conjugated with multiple NMR-active nuclei (such as 13C, 15N, or 19F labels). This composite structure enhances the NMR signal intensity and improves the signal/noise ratio while maintaining the ability to detect enzyme activity through relaxation changes.
Solution Approach 2:
The invention changes the physical parameters of the probe by introducing multiple NMR-active nuclei with different resonance frequencies. This increases the sensitivity of detection and allows for multi-dimensional NMR measurements, thereby improving the signal/noise ratio without requiring complex probe structures.
2Measurement precision
If luminescent or fluorescent probes are used to detect enzyme activity, then the detection sensitivity can be improved, but it is difficult to capture signals from deep parts of the living body due to low light permeability and scattering
Solution Approach 1:
The invention replaces optical detection methods (luminescent/fluorescent probes) with NMR-based detection. NMR signals are electromagnetic waves in the radiofrequency range that can penetrate deep into biological tissues without significant scattering or absorption, thereby maintaining high detection sensitivity while overcoming the limitation of light permeability.
3Measurement precision
If probes are chemically modified and labeled to detect enzyme activity, then the detection capability is enhanced, but the specificity of the probe to substrate decreases
Solution Approach 1:
The invention introduces NMR-active nuclei at specific local positions on the substrate molecule (such as at the scissile bond or near the enzyme recognition site). This localized labeling enhances detection capability while minimizing interference with the overall substrate structure and enzyme-substrate recognition, thereby maintaining probe specificity.
4Object-affected harmful factors
If probes are used with limited dosing due to low biocompatibility, then the safety is improved, but the signal/noise ratio decreases
Solution Approach 1:
The invention uses the natural NMR properties of the substrate molecule itself (or minimally modified substrate) as the detection mechanism. The substrate acts as its own probe, eliminating the need for complex labeling that would reduce biocompatibility. By using endogenous metabolic pathways and natural NMR-active nuclei, the system achieves both high biocompatibility and sufficient signal/noise ratio.
Data Source
AI summary
Substrate probe capable of detecting enzyme activity with high accuracy and a method for detecting the enzyme activity by a multi nuclear magnetic resonance method using the substrate probe. Multi-dimensional nuclear magnetic resonance is performed by using a substrate probe, which is used for measuring enzyme activity by a multi-dimensional nuclear magnetic resonance method and characterized by containing a enzyme recognition site that is selectively recognized by an active-state enzyme, as at least one constitutional unit, and a group to which at least three nuclear magnetic resonance active nuclei each having a nuclear spin and a different resonance frequency are connected, being present specifically to the enzyme recognition, thereby detecting presence of the substrate probe and the enzyme activity.