Chemically Modified Lys-C Proteases for Autolysis-Resistant LC-MS
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Solution Overview
Problem
Proteases used in analytical applications such as LC-MS suffer from autolysis, producing undesirable peptide byproducts that obscure detection peaks of relevant protein analytes, contaminating samples and reducing measurement sensitivity and specificity.
Innovation Solution
Chemically modify protease enzymes like Lys-C and Lys-N at specific lysine residues with alkylations, acetylations, or amidinations to enhance their autolysis resistance, reducing the production of peptide byproducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If proteases are used for analytical applications, then protein sequencing and peptide mapping can be performed, but protease autolysis produces peptide byproducts that obscure detection peaks and contaminate samples
Solution Approach 1:
The patent applies chemical modification to change the chemical parameters of lysine residues in the protease enzyme. By modifying these residues through alkylation, acetylation, or other chemical reactions, the enzyme's autolysis is suppressed while its proteolytic activity is maintained, resolving the contradiction between productivity and harmful byproduct generation
Solution Approach 2:
The patent converts the harmful autolysis process into a beneficial outcome by using chemical modification to selectively prevent self-digestion. The modification transforms the enzyme's reactive lysine residues into a state that prevents autolysis while preserving its ability to digest target proteins, effectively turning the harmful self-cleavage mechanism into a controlled, beneficial process
2Productivity
If proteases are used for protein analysis, then quality control testing can be performed, but measurement precision is reduced due to interfering peptide peaks
Solution Approach 1:
The patent extracts and removes the source of interference by chemically modifying the protease enzyme to prevent autolysis. This eliminates the generation of interfering peptide byproducts that would otherwise appear as false peaks in LC-MS analysis, thereby improving measurement precision while maintaining analytical capability
3Productivity
If proteases are used for peptide mapping, then protein sequencing can be achieved, but specificity is reduced due to contaminating peptide byproducts
Solution Approach 1:
The patent modifies the chemical parameters of the protease enzyme through chemical modification of lysine residues. This changes the enzyme's properties to suppress autolysis while maintaining its sequencing capability, thereby improving the reliability of peptide identification by eliminating contaminating byproducts
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
Enhances autolysis resistance by up to 1000% or more, minimizing interference and improving the sensitivity and specificity of LC-MS analyses by reducing protease-derived peptide contaminants.
Implementation Method 1
protease enzymes with lysine cleavage specificity, such as Endopeptidase Lys-C (Lys-C) or Lys-N (Peptidyl-Lys Metalloendopeptidase), that are chemically modified (e.g., alkylated, acetylated, amidinated, or guanidinated) at lysine residues to impart enhanced autolysis resistance to the enzymes
Data Source
AI summary
The present disclosure relates to chemically modified protease enzymes, Lys-C and Lys-N, that have enhanced autolysis resistance. Also disclosed herein are methods of using such protease enzymes for improving detection of target analyte proteins in an analytical assay.