Solid-Phase Radiolabeling of Polypeptides via Phosphine Binding Groups
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Solution Overview
Problem
Current methods for radiolabeling peptides and polypeptides are inefficient due to interference from free cysteine or histidine side chains competing with chelating groups for metal ion binding, leading to reduced yields and dependency on specific amino acid sequences.
Innovation Solution
A method involving solid phase synthesis where a polypeptide is first linked to a non-complexed binding group, allowing for direct labeling with commercially available radioactive metals in low concentrations, using optionally substituted aryl or heteroaryl phosphine derivatives as binding groups, which can be covalently linked to the polypeptide, enabling standardized and automated labeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional radiolabeling methods are used, then labeling can be performed on peptides, but free cysteine or histidine side chains interfere with chelating groups for metal ion binding, leading to reduced yields
Solution Approach 1:
The patent applies preliminary action by first covalently linking the polypeptide to a solid support matrix before introducing the chelating group and performing radiolabeling. This sequential approach ensures that the polypeptide is immobilized and positioned optimally, preventing interference from free cysteine or histidine side chains during the metal ion binding step, thereby achieving high radiolabeling yields
Solution Approach 2:
The patent uses a solid support matrix as an intermediary between the polypeptide and the chelating group. The matrix facilitates controlled introduction of the chelating group to the immobilized polypeptide, ensuring that metal ions bind selectively to the chelating group rather than to interfering side chains, thus resolving the contradiction between productivity and harmful interference
2Ease of manufacture
If conventional radiolabeling methods are used, then peptides can be labeled, but the process is complex and dependent on specific amino acid sequences
Solution Approach 1:
The patent achieves universality by developing a standardized solid-phase synthesis protocol that can be applied to any polypeptide sequence. The method uses universal reagents and conditions for polypeptide immobilization, chelating group introduction, and radiolabeling, making the process independent of specific amino acid sequences while simplifying manufacturing
Solution Approach 2:
The patent applies parameter changes by optimizing reaction conditions such as solvent composition, temperature, and reagent concentrations for the solid-phase synthesis process. These standardized parameter settings enable consistent radiolabeling across different polypeptide sequences, reducing process complexity and eliminating sequence dependency
3Extent of automation
If polypeptides are labeled with radioactive metals, then imaging reagents and radiation therapeutics can be produced, but the labeling process is time-consuming and not easily automated
Solution Approach 1:
The patent applies segmentation by dividing the radiolabeling process into discrete, modular steps: polypeptide immobilization on solid support, chelating group introduction, and radioactive metal labeling. Each step can be performed independently and optimized for automation, enabling the entire process to be implemented on automated synthesizers and significantly reducing manual intervention time
Solution Approach 2:
The patent implements continuity of useful action by maintaining the polypeptide in an immobilized state throughout the entire radiolabeling process. This eliminates time-consuming isolation and purification steps between reactions, allowing continuous processing and automation while minimizing total labeling time
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method simplifies and standardizes the radiolabeling process, allowing for efficient labeling of peptides with low radioactive metal concentrations and reducing interference from reactive side chains, resulting in high radiochemical yields and purity.
Implementation Method 1
BG is a (non-complexed) binding group for a metal M selected from the group consisting of 99mTc, 68Ga, 44Sc, 64Cu, 188Re, 186Re, 111In and 86Y
Data Source
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AI summary
The invention relates to a compound of the formula (I) T-Pep-BG (I) where, in formula (I), T is a solid support; Pep is a polypeptide bonded covalently to T, where the polypeptide has an amino acid sequence having 3 to 200 amino acids and BG is an uncomplexed binding group for a metal M selected from the group consisting of 99mTc,186Re,188Re, 90Y, 86Y, 177Lu, 68Ga, 67Cu, 64Cu, 67Ga,89Zr,153Sm and 111 In. The invention further relates to a method for preparing the compound of the formula (I) and to uses and kits of the compounds of the formula (I) for production of radiodiagnostic and radiotherapeutic products.