Modified Glucagon Phosphorylation for Neutral-pH Solubility
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Solution Overview
Problem
Glucagon's poor water solubility at neutral pH and instability lead to irreversible amyloid fibril formation, compromising its potency and safety for delivery via infusion pumps or injection pens, hindering its use in closed-loop artificial pancreas devices.
Innovation Solution
Phosphorylation of specific amino acid residues in the glucagon molecule, such as Thr5 and Ser8, introduces charged and hydrophilic groups into the hydrophobic steric zipper core, preventing fibril formation and enhancing solubility at neutral pH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If glucagon is formulated as a lyophilized powder to maintain stability, then stability is improved, but ease of operation deteriorates due to requiring reconstitution and discarding surplus
Solution Approach 1:
The patent modifies the chemical structure of glucagon by phosphorylating specific amino acid residues (Thr5, Ser8, and/or Ser16), which changes the molecular properties to improve water solubility at neutral pH while maintaining stability, eliminating the need for lyophilization and reconstitution
Solution Approach 2:
The patent creates a composite modification by combining glucagon with phosphate groups at specific positions, resulting in a phosphorylated glucagon derivative that exhibits both improved solubility and stability properties simultaneously
2Quantity of substance
If glucagon is solubilized in acidic pH to improve solubility, then solubility is improved, but stability deteriorates due to irreversible amyloid fibril formation
Solution Approach 1:
The patent changes the pH parameter from acidic to neutral by modifying the glucagon molecule through phosphorylation, which introduces charged groups that prevent fibril formation and maintain both solubility and stability at neutral pH
Solution Approach 2:
The patent converts the harmful hydrophobic interactions that cause fibril formation into beneficial hydrophilic interactions through phosphorylation, where the introduced phosphate groups disrupt the steric zipper formation while maintaining solubility
3Quantity of substance
If phosphorylated amino acids are introduced to improve solubility at neutral pH, then solubility is improved, but manufacturing precision deteriorates due to complex modification requirements
Solution Approach 1:
The patent applies phosphorylation at specific local positions (Thr5, Ser8, and/or Ser16) rather than uniform modification throughout the molecule, which maintains manufacturing feasibility while achieving the desired solubility improvement through targeted changes
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
The modified glucagon molecules, or phosphoglucagons, maintain stability and solubility at neutral pH, preventing fibrillation and enabling stable formulations for current uses and expanding therapeutic applications.
Implementation Method 1
Phosphorylation of specific amino acid residues in the glucagon molecule, such as Thr5 and Ser8, introduces charged and hydrophilic groups into the hydrophobic steric zipper core, preventing fibril formation and enhancing solubility at neutral pH
Implementation Method 2
Amyloid β-fibrils are long β-sheets known as β-spines that interact side-by-side by entanglement of their side chains, forming a steric zipper
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The invention generally relates to modified glucagon molecules. In certain embodiments, the invention provides a glucagon molecule that includes one or more modified amino acids to result in the glucagon molecule being soluble at a substantially neutral pH and resistant to fibrillation.