Enzymatic Perfusion Fluid for A-Antigen Cleavage
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Solution Overview
Problem
Current enzyme compositions for cleaving carbohydrate antigens from blood cells are inefficient, requiring substantial amounts of enzymes, especially for Type A blood, limiting their practical application in transfusion medicine and organ perfusion.
Innovation Solution
A combination of Galactosaminidase and GalNAcDeacetylase enzymes, specifically purified proteins from Flavonifractor plautii and Clostridium tertium, are used in a perfusion fluid to efficiently cleave A-antigens at low concentrations, maintaining viability and activity across a wide temperature and pH range, with the addition of a crowding agent like dextran enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional enzymes (α-galactosidase from green coffee bean or GH109/GH110 glycosidases) are used to cleave A-antigens, then antigen removal capability is achieved, but substantial amounts of enzyme are required (60 mg enzyme/unit of blood), making the approach impractical
Solution Approach 1:
The patent combines two enzymes - GalNAcDeacetylase and Galactosaminidase - into a synergistic system. The GalNAcDeacetylase first removes the acetyl group from the terminal GalNAc residue, and the Galactosaminidase then cleaves the resulting galactosamine linkage. This two-step combined action achieves complete A-antigen removal at much lower total enzyme concentrations than conventional single-enzyme approaches, directly resolving the contradiction between enzyme quantity required and cleavage efficiency.
Solution Approach 2:
The A-antigen cleavage process is divided into two sequential enzymatic steps: (1) deacetylation of the terminal GalNAc by GalNAcDeacetylase, and (2) cleavage of the galactosamine linkage by Galactosaminidase. This segmentation of the complex antigen removal process into manageable steps allows each enzyme to act optimally on its specific substrate, improving overall efficiency and reducing the total enzyme amount needed.
2Productivity
If high enzyme concentrations are used to improve cleavage efficiency, then antigen removal is enhanced, but the time required for perfusion increases and cellular viability may be compromised
Solution Approach 1:
The patent optimizes multiple parameters including pH (maintained between 6.5-7.5 to ensure enzyme activity and cell viability), temperature (4°C-37°C range compatible with blood storage and handling), and enzyme concentration (reduced to ≤1 μg/ml through the combined system). These parameter optimizations enable efficient antigen cleavage to occur rapidly without compromising cell viability or requiring excessive perfusion time.
3Quantity of substance
If enzyme concentration is reduced to decrease cost and improve logistics, then practical application is enhanced, but antigen cleavage efficiency decreases
Solution Approach 1:
The patent introduces a crowding agent (such as dextran) as an intermediary substance that enhances enzyme activity. The crowding agent increases the local concentration of enzymes and substrates, improving the collision frequency and reaction rate. This allows the system to maintain high antigen cleavage efficiency even at very low enzyme concentrations (≤1 μg/ml), resolving the contradiction between enzyme quantity and 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
The enzyme combination achieves significant A-antigen cleavage at concentrations as low as 1 μg/ml, allowing for efficient conversion of blood types and organ perfusion, reducing the time required for perfusion or the amount of enzymes needed, while maintaining cellular viability.
Implementation Method 1
a purified enzyme having a GalNAcDeacetylase activity consisting essentially of an amino acid sequence at least 90% identical to the sequence set forth in one of SEQ ID NOs: 2, 4, 5, 17, 23, 29, 31 and 32-35
Implementation Method 2
The concept of enzymatic removal of the GalNAc or Gal structures from A or B RBCs as a means of converting A or B RBCs to O was first proposed and demonstrated by Goldstein
Implementation Method 3
a purified enzyme having Galactosaminidase activity consisting essentially of an amino acid sequence at least 90% identical to the sequence set forth in one of SEQ ID NOS: 7, 9, 10, 19, 21, 36 and 37
Implementation Method 4
Two new families of glycosidase were found that show high antigen cleavage activity at neutral pH values: the CAZy GH109 α-N-acetylgalactosaminidases and the GH110 α-galactosidases
Implementation Method 5
the efficiency of the enzymes is further improved through the addition of a crowding agent (for example, dextran)
Data Source
AI summary
Provided herein are perfusion fluids for enzymatically cleaving A-antigens from a donor organ, and methods. uses. associated therewith. In particular, the perfusion fluids comprise two enzymes. GalNAcDeacetylase and Galactosaminidase and the fluids may further comprise a buffered extracellular solution and/or a crowing agent. Furthermore. the compositions described herein were found to have activity at temperatures and ph levels suitable for cell viability.