pH-Tagged Polypeptide Purification for Low-Cytotoxicity Activity Testing
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Solution Overview
Problem
Existing methods for evaluating the physiological activity of special polypeptides synthesized via cell-free expression face challenges due to low concentration and cytotoxicity issues, making it difficult to assess their activity effectively.
Innovation Solution
A method involving affinity purification using a pH-responsive affinity tag, followed by elution with low-concentration acidic or basic solutions and neutralization to prepare a polypeptide solution for evaluation, which reduces cytotoxicity and maintains a high concentration for physiological activity assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If dilution is performed after cell-free expression to enable activity evaluation, then cytotoxicity is reduced, but polypeptide concentration becomes insufficient for evaluation
Solution Approach 1:
The patent extracts and removes toxic components from the cell-free expression system through affinity purification. The polypeptide is specifically bound to an affinity column while toxic components remain in the supernatant and are discarded, thereby eliminating cytotoxicity without requiring dilution that would reduce polypeptide concentration.
Solution Approach 2:
The affinity purification step serves multiple functions simultaneously: it concentrates the polypeptide by selective binding, removes toxic components through differential retention, and prepares the sample for activity evaluation in a single integrated process, resolving both the cytotoxicity and concentration issues.
2Object-affected harmful factors
If affinity purification is performed to remove toxic components, then cytotoxicity is reduced, but additional cost and time are required
Solution Approach 1:
The patent combines the purification function with the activity evaluation preparation in a single affinity purification step. The same binding and elution process that removes toxic components also concentrates the polypeptide to the required evaluation concentration, eliminating the need for separate purification and concentration steps.
Solution Approach 2:
The affinity tag on the polypeptide enables self-selective binding to the affinity column without requiring additional reagents or complex purification protocols. The polypeptide automatically binds to its specific ligand on the column, allowing rapid purification that minimizes time loss.
3Object-affected harmful factors
If affinity purification is performed to remove toxic components, then cytotoxicity is reduced, but polypeptide loss occurs
Solution Approach 1:
The patent optimizes the elution conditions by adjusting pH and ionic strength parameters to maximize polypeptide recovery. The elution buffer is carefully designed to release the bound polypeptide efficiently while maintaining its activity, thereby minimizing loss during the purification process that removes toxic components.
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
Enables convenient and efficient evaluation of physiological activity at a high polypeptide concentration, minimizing cytotoxicity and loss, while allowing for rapid and cost-effective preparation of the polypeptide solution.
Implementation Method 1
bringing a crude polypeptide solution after cell-free expression into contact with a carrier to bind a polypeptide having a pH-responsive affinity tag to the carrier
Implementation Method 2
eluting the polypeptide bound to the carrier with an acidic aqueous solution or a basic aqueous solution
Implementation Method 3
adding a basic aqueous solution or an acidic aqueous solution to the eluted solution to neutralize an acid or a base contained in the eluted solution, and neutralizing in such a manner that a concentration of a salt formed by a neutralization reaction is less than 50 mM
Data Source
AI summary
A method for preparing a polypeptide solution for evaluating a physiological activity and A method for evaluating a physiological activity of a polypeptide, the method includes: (A) bringing a crude polypeptide solution after cell-free expression into contact with a carrier to bind a polypeptide having a pH-responsive affinity tag to the carrier; (B) eluting the polypeptide bound to the carrier with an acidic aqueous solution or a basic aqueous solution, each having a concentration of less than 50 mM, to obtain an eluted solution; and (C) adding a basic aqueous solution or an acidic aqueous solution to the eluted solution to neutralize an acid or a base contained in the eluted solution, and neutralizing in such a manner that a concentration of a salt formed by a neutralization reaction is less than 50 mM, to obtain a polypeptide solution.