Peptide Mapping Using LC-MS Compatible Buffers
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Solution Overview
Problem
Current peptide mapping methods for protein analysis are time-consuming and costly, requiring multiple steps and salt-based buffers that are not compatible with LC-MS, making it difficult to efficiently determine the identity and sequence of insulin and its analogues, especially in complex samples.
Innovation Solution
A method involving the digestion of polypeptides with endoproteinase Glu C, followed by reduction and HPLC analysis using a non-salt buffer, allowing for rapid sequence confirmation and mass determination of peptides like insulin and its analogues, reducing the overall processing time to around 40 minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional peptide mapping methods are used, then protein identification and sequence confirmation are achieved, but the process is time-consuming (up to two working days) and costly due to multiple steps and chemicals
Solution Approach 1:
The invention extracts and eliminates the desalting step from the conventional peptide mapping workflow. By using LC-MS compatible buffers from the beginning, the method removes the time-consuming desalting operation that traditionally took hours, reducing total processing time to under 2 hours while maintaining identification accuracy
Solution Approach 2:
The invention performs preliminary buffer exchange and sample preparation in LC-MS compatible buffers before analysis begins. This preliminary action eliminates the need for subsequent desalting steps, allowing direct injection into the LC-MS system and significantly reducing overall processing time
2Measurement precision
If salt-based peptide mapping methods are used, then protein analysis is performed, but the method is not compatible with LC-MS usage
Solution Approach 1:
The invention changes the buffer composition parameters from salt-based to volatile, LC-MS compatible buffers throughout the entire workflow. This parameter change enables direct compatibility with LC-MS detection while maintaining peptide mapping accuracy, as the volatile buffers do not interfere with mass spectrometry analysis
3Measurement precision
If conventional desalting and multiple chromatographic runs are performed, then individual fragments are detected, but the process requires up to two working days
Solution Approach 1:
The invention merges multiple separate operations (chromatographic runs, desalting, individual fragment analysis) into a single integrated LC-MS analysis. By using compatible buffers and direct injection, multiple fragments are detected simultaneously in one run, dramatically increasing productivity from one fragment per run to multiple fragments per analysis
Solution Approach 2:
The invention maintains continuous analysis by eliminating idle time between steps. The workflow proceeds continuously from sample preparation in LC-MS compatible buffers through direct injection and detection of multiple fragments in a single uninterrupted LC-MS run, maximizing productivity
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 significantly reduces the time and cost of peptide mapping by eliminating the desalting step and enabling the simultaneous detection of multiple fragments, providing reliable sequence confirmation and mass analysis of peptides up to 50 kDa within a shorter timeframe.
Implementation Method 1
digestion of the polypeptide sample by addition of endoproteinase Glu C
Implementation Method 2
reduction of digested sample
Implementation Method 3
performing HPLC analysis
Data Source
AI summary
The invention relates to peptide mass fingerprinting technique for the proteins such as Human insulin and insulin analogs. The insulin analogues can vary at least by one amino acid, which is elusive to distinguish by currently available analytical methods. The invention further allows sequence confirmation of the peptide wherein the run time of the method is forty minutes. This method could be applied for molecules up to 50 kDa.