Sequential Polypeptide Digestion for Simpler Peptide Mapping
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Solution Overview
Problem
Conventional multiple enzyme digestion methods for polypeptides result in complex digests with numerous peaks or require separate analysis, complicating the interpretation of mass spectrometry-based analysis.
Innovation Solution
A sequential enzymatic digestion method using two or more proteases, where high molecular weight peptides are separated and further digested individually, followed by combining all digests for a single peptide map analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple enzymes are used together in conventional digestion, then complete cleavage of polypeptides is achieved, but the digest becomes complicated with too many peaks
Solution Approach 1:
The patent applies segmentation by dividing the polypeptide digestion process into sequential stages using different enzymes at different times. First, a primary enzyme (e.g., trypsin) performs initial cleavage, then large peptide fragments are separated and further digested with secondary enzymes (e.g., chymotrypsin, elastase). This segmented approach ensures complete cleavage while maintaining manageable digest complexity at each stage.
Solution Approach 2:
The patent employs preliminary action by performing initial digestion with a primary enzyme before introducing secondary enzymes. The first digestion step prepares the polypeptide by creating initial fragments, which are then separated by size. This preliminary processing allows subsequent enzymes to work on pre-sized fragments, preventing the accumulation of excessive peak complexity.
2Reliability
If multiple enzymatic digestions are performed separately, then interference among enzymes is avoided, but multiple separate analyses are required
Solution Approach 1:
The patent resolves the contradiction by adding a temporal dimension to the digestion process. Instead of performing multiple digestions simultaneously (same time dimension) or completely separately (multiple analyses), the invention sequences enzyme actions in time while combining results in a unified analysis. The sequential timing allows enzyme specificity to be maintained while the combined final analysis improves productivity.
3Device complexity
If single enzyme digestion is used, then the digest is simple to analyze, but large peptides are produced that are challenging to analyze
Solution Approach 1:
The patent applies local quality by applying different enzymatic conditions to different portions of the polypeptide at different stages. The primary enzyme performs initial cleavage across the entire polypeptide, then secondary enzymes are applied specifically to the separated large fragments. This localized, staged enzymatic action produces appropriately sized peptides for analysis while maintaining overall digest simplicity.
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 approach simplifies the analysis by reducing peak complexity and enabling efficient, unified interpretation of polypeptide samples using mass spectrometry.
Implementation Method 1
a. cleaving the polypeptide in a first digestion, wherein the cleaving produces at least two fragments of the polypeptide
Data Source
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AI summary
The disclosed methods are directed to preparing polypeptides for multi]attribute analysis. The polypeptides are optionally denatured, reduced, and/or alkylated before being subjected to a first digestion. Following the first digestion the large and small fragments resulting from the digestion are separated from each other. A second digestion is then performed on the larger of the fragments. All of the fragments from the two digestions are then analyzed chromatographically, electrophoretically, or spectrometrically, or a combination of these methods. The methods are especially useful for the preparation of therapeutic polypeptides for analysis, especially those that are not easily cleaved.