Modified DAAO Enzyme Stability and Activity for L-Glufosinate
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Solution Overview
Problem
Current methods for producing L-glufosinate from D,L-glufosinate are inefficient due to high costs, multiple reaction steps, and low substrate concentration, primarily due to the instability and limited catalytic activity of recombinant D-amino acid oxidase (DAAO) enzymes.
Innovation Solution
A modified D-amino acid oxidase (DAAO) with specific amino acid substitutions at positions 54, 56, 58, 213, and other positions is developed to enhance its stability and activity for catalyzing the oxidation of D-glufosinate into 2-carbonyl-4-(hydroxymethylphosphono)butyric acid (PPO), improving the efficiency of L-glufosinate production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type DAAO is used to catalyze the oxidation of D-glufosinate, then the reaction can proceed, but the enzyme exhibits low stability and limited catalytic activity
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of DAAO through site-directed mutagenesis. Specific amino acid residues (e.g., positions 54, 56, 58, 213, 221, 237, 265, 273, 274, 300, 317, 319, 337, 342) are substituted to alter the enzyme's physical and chemical properties, thereby improving both stability and catalytic activity simultaneously.
Solution Approach 2:
The patent applies local quality by making targeted amino acid substitutions at specific positions within the enzyme structure. Rather than modifying the entire enzyme uniformly, specific local regions (active site, substrate binding pocket, structural domains) are modified to enhance particular functions while maintaining overall enzyme integrity.
2Manufacturing precision
If traditional resolution method by chemical modification is used, then D,L-glufosinate can be resolved, but the cost is high and D-glufosinate cannot be utilized
Solution Approach 1:
The patent replaces chemical modification methods with enzymatic catalysis. Instead of using chemical reagents to resolve D,L-glufosinate, a modified DAAO enzyme is used to selectively oxidize D-glufosinate, providing a more cost-effective and environmentally friendly approach that utilizes the substrate directly.
Solution Approach 2:
The patent enables the substrate D-glufosinate to serve its own purpose in the reaction. Rather than requiring chemical modification of protecting groups or auxiliary reagents, the enzyme catalyzes the oxidation of D-glufosinate directly, making the substrate itself the reactant of choice.
3Manufacturing precision
If multiple reaction steps are used to convert D,L-glufosinate to L-glufosinate, then chiral pure L-glufosinate can be obtained, but the process complexity increases
Solution Approach 1:
The patent extracts and utilizes the stereoselective oxidation capability of DAAO to directly convert D-glufosinate to PPO, simplifying the multi-step process. By focusing on the key stereoselective step and using enzyme catalysis, the patent reduces the number of required reaction steps while maintaining high chiral purity.
4Productivity
If high substrate concentration is used to improve production efficiency, then output increases, but enzyme inactivation occurs due to instability
Solution Approach 1:
The patent applies beforehand cushioning by pre-modifying the enzyme structure through amino acid substitutions to enhance its stability before exposure to high substrate concentrations. The modified enzyme is prepared in advance with improved stability characteristics, allowing it to withstand harsh reaction conditions without inactivation.
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 DAAO exhibits increased stability and activity, enabling higher conversion rates of D-glufosinate to PPO, thereby reducing production costs and improving the efficiency of L-glufosinate synthesis.
Implementation Method 1
D-amino acid oxidase (DAAO) is used to catalyze the oxidation of D-glufosinate into PPO
Implementation Method 2
modified D-amino acid oxidase (DAAO) with specific amino acid substitutions at positions 54, 56, 58, 213, and other positions is developed to enhance its stability and activity for catalyzing the oxidation of D-glufosinate
Data Source
AI summary
The present invention refers to a modified D-amino acid oxidase (DAAO). In particular, the modified DAAO of the present invention has the activity of catalyzing the oxidation of D-glufosinate into PPO. Further, the modified DAAO of the present invention has increased activity of catalyzing the oxidation of D-glufosinate into PPO and/or increased stability as compared to SEQ ID NO: 4. The present invention also refers to the polynucleotide encoding the modified DAAO of the present invention, the vector and host cell expressing the modified DAAO of the present invention, and the method of producing L-glufosinate with the modified DAAO and host cell of the present invention.