Engineered Penicillin G Acylase Mutations for Stable Insulin Deprotection
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Solution Overview
Problem
Naturally occurring penicillin G acylase enzymes are unstable in commercial processes, leading to reduced activity and selectivity when immobilized on solid substrates, limiting their effectiveness in producing 6-aminopenicillanic acid and compromising enzyme stability and solute access.
Innovation Solution
Engineered penicillin G acylases with specific mutations, such as those represented by SEQ ID NO:2, 4, 6, 8, 10, and/or 12, capable of removing A1/B1/B29 tri-phenyl acetate protecting groups from insulin to produce free insulin, exhibiting improved enzymatic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If penicillin G acylase is immobilized on solid substrates, then enzyme capture and reuse are enabled, but enzyme activity and selectivity are reduced
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid mutations (e.g., Phe194Leu, Trp198Phe) to modify the enzyme's physical and chemical properties. These mutations enhance the enzyme's stability and activity simultaneously, resolving the contradiction between immobilization benefits and activity loss. The mutated enzyme maintains higher catalytic efficiency while being immobilized on solid supports.
Solution Approach 2:
The patent applies local quality by making site-specific mutations at particular amino acid positions (194, 198, etc.) rather than global modifications. These localized changes specifically target regions involved in substrate binding and catalysis, preserving activity while improving overall stability during immobilization processes.
2Reliability
If penicillin G acylase is immobilized on solid substrates, then enzyme reuse is possible, but solute access is limited
Solution Approach 1:
The patent uses parameter changes through mutations like Phe194Leu that increase the enzyme's structural flexibility and openness. This allows better penetration of solutes into the immobilized enzyme structure, improving access to active sites while maintaining the stability benefits of immobilization.
3Productivity
If penicillin G acylase is used in commercial processes, then 6-APA production is achieved, but enzyme instability limits process effectiveness
Solution Approach 1:
The patent applies parameter changes through multiple amino acid substitutions that collectively enhance the enzyme's thermal and operational stability. The mutated enzyme maintains high activity over extended periods in commercial-scale 6-APA production processes, overcoming the instability limitation of wild-type PGA.
Solution Approach 2:
The patent creates a composite enzyme system by combining multiple mutations (Phe194Leu, Trp198Phe, and others) to produce an enzyme with enhanced properties. This composite approach synergistically improves both stability and productivity for industrial applications.
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 engineered enzymes demonstrate enhanced stability and activity, allowing for efficient production of free insulin with high yield and improved enzymatic performance compared to wild-type enzymes.
Implementation Method 1
capable of removing the A1/B1/B29 tri-phenyl acetate protecting groups from insulin to produce free insulin
Implementation Method 2
Penicillin G acylase (PGA) (penicillin amidase, EC 3.5.1.11) catalyzes the cleavage of the amide bond of penicillin G (benzylpenicillin) side chain
Data Source
AI summary
The present disclosure relates to engineered penicillin G acylase (PGA) enzymes having improved properties, polynucleotides encoding such enzymes, compositions including the enzymes, and methods of using the enzymes.