Site-Specific PEGylation for Uniform Heteromeric Protein Drugs

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Solution Overview

Problem

Existing PEGylation technologies for proteins and polypeptides often result in non-uniform structures due to random modifications, leading to batch-to-batch variability and safety uncertainties, especially when applied to heteromeric proteins or polypeptides with multiple free cysteine thiol groups.

Innovation Solution

A method for site-specific PEGylation of heteromeric proteins or polypeptides by blocking non-target N-terminal α-amino groups and reacting aldehyde or ketone derivatives of polyethylene glycol with the retained target N-terminal α-amino groups, using gene mutation and expression in host cells to achieve controlled modification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If random modification and multiple modifications are used in early PEGylation, then the modification process is simple and fast, but the drug structure becomes non-uniform and batch-to-batch variability increases

Engineering Contradiction:
ImprovePEGylation speedVSAvoiddrug structure uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by transitioning from random modification to site-specific modification at predetermined locations on the protein structure. This ensures uniform drug structure at the modification site while maintaining overall protein functionality, resolving the contradiction between modification speed and structural uniformity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs preliminary action by pre-determining and pre-positioning the modification sites on the protein structure before performing PEGylation. This planning phase ensures that subsequent modification occurs at specific locations, achieving both efficiency and uniformity without batch-to-batch variability.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If site-specific modification with a single PEG is used, then the drug structure becomes uniform and defined, but the method only works on single-chain proteins or proteins with a single free cysteine thiol group

Engineering Contradiction:
Improvedrug structure uniformityVSAvoidapplicability to heteromeric proteins
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent achieves universality by developing a site-specific PEGylation method that can be applied to various protein types including heteromeric proteins with multiple subunits and multiple free cysteine thiol groups. The method uses predetermined modification sites that can be positioned on different subunits, making it universally applicable while maintaining structural uniformity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies segmentation by addressing each subunit of heteromeric proteins independently, allowing site-specific modification on specific subunits while leaving others unchanged. This segmented approach enables the method to handle complex heteromeric structures with multiple modification sites without compromising uniformity.

Inventive Principle:
Principle #1Segmentation

3Object-generated harmful factors

If multiple free cysteine thiol groups are present in heteromeric proteins, then the protein has high reactivity and functionality, but random PEGylation occurs at multiple sites leading to non-uniform structure

Engineering Contradiction:
Improveprotein reactivityVSAvoidmodification site consistency
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by selectively modifying only specific local regions (predetermined sites) on the protein structure while leaving other reactive regions unchanged. This ensures consistent modification sites even in proteins with multiple free cysteine thiol groups, maintaining both reactivity and precision.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses an intermediary approach by introducing a specific reagent or catalyst that directs the PEGylation reaction to predetermined sites only, preventing random modification at other cysteine thiol groups. This intermediary mechanism ensures modification consistency despite the presence of multiple reactive sites.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method provides a defined and controllable modification position, extending half-life and activity of the modified products, suitable for drug treatment applications with consistent structure and safety.

Implementation Method 1

reacting an aldehyde derivative or ketone derivative of polyethylene glycol with the retained N-terminal α-amino group

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Data Source

PatentEP4617281A1Site-specific pegylated heteromeric protein or polypeptide, and preparation method therefor and use thereof
Publication Date: 2025.09.17 KANGLITAI BIOMEDICAL (QINGDAO) CO LTD
  • EP4617281A1 patent drawingFigure 1~4
  • EP4617281A1 patent drawingFigure 5~7
  • EP4617281A1 patent drawingFigure 8~11

AI summary

Provided is a site-specifically PEGylated heteromeric protein or polypeptide and a preparation method and use of the heteromeric protein or polypeptide. First, a method for site-specific PEGylation of a protein or polypeptide is provided. The method includes: providing a protein or polypeptide to be modified, the protein or polypeptide to be modified including a target N-terminal α-amino group and a non-target N-terminal α-amino group, and mutating and blocking the non-target N-terminal α-amino group; and subjecting the target N-terminal α-amino group to a site-specific modification reaction with an aldehyde or ketone derivative of polyethylene glycol to generate a site-specifically PEGylated protein or polypeptide. Heteromeric protein or polypeptide products subjected to site-specific single modification with polyethylene glycol by this method has a specific and controllable modification position, which can bring about a clearly extended half-life and biased composition activity, and can be better applied to drug treatment purposes.