Reduced Vitamin K Forms for Protein Expression Yield
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Solution Overview
Problem
Current methods for producing vitamin K-dependent proteins, such as Factor IX, in genetically engineered cells face challenges with incomplete post-translational modification and reduced activity due to limitations in enzymatic activities, leading to undercarboxylated proteins with impaired functionality.
Innovation Solution
Supplementing cell culture media with reduced forms of vitamin K, vitamin K analogs, or vitamin K precursors to enhance the expression and activity of vitamin K-dependent proteins by increasing gamma-carboxylation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional vitamin K supplementation methods are used in cell culture media, then some gamma-carboxylation activity is achieved, but the expression yield and biological activity of vitamin K-dependent proteins remain insufficient
Solution Approach 1:
The patent applies parameter changes by switching from conventional oxidized vitamin K (menadione) to reduced vitamin K forms (vitamin K hydroquinone or vitamin K dihydroquinone) in the cell culture media. This chemical state change enables the vitamin K-dependent carboxylase enzyme to efficiently carboxylate glutamic acid residues, producing fully active vitamin K-dependent proteins with complete gamma-carboxylation modification and significantly higher expression yields.
2Reliability
If high concentrations of vitamin K are added to cell culture media to increase protein activity, then gamma-carboxylation efficiency improves, but the cost and complexity of the production process increase
Solution Approach 1:
The patent simplifies the production process by using reduced vitamin K forms that are directly effective at lower concentrations. The vitamin K hydroquinone or dihydroquinone forms are readily taken up by cells and immediately available for the carboxylation reaction, eliminating the need for complex high-concentration supplementation protocols and reducing overall process complexity while maintaining high protein biological activity.
3Productivity
If oxidized vitamin K (menadione) is used for supplementation, then some carboxylation activity is supported, but cellular uptake and metabolic conversion to active forms are inefficient
Solution Approach 1:
The patent applies preliminary action by providing vitamin K already in the reduced hydroquinone or dihydroquinone form, which is the direct substrate for the gamma-glutamyl carboxylase enzyme. This eliminates the need for cells to perform energy-consuming reduction reactions on oxidized vitamin K, allowing immediate and efficient carboxylation of vitamin K-dependent proteins without additional metabolic activation steps.
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
Significantly increases the yield and activity of biologically active vitamin K-dependent proteins, improving their functionality and reducing the need for high vitamin K concentrations, thereby addressing the limitations of existing production methods.
Implementation Method 1
Another enzyme then oxidizes vitamin K hydroquinone to allow carboxylation of Glu to Gla; this enzyme is called the gamma-glutamyl carboxylase or the vitamin K-dependent carboxylase (VKGC). The carboxylation reaction will only proceed if the carboxylase enzyme is able to oxidize vitamin K hydroquinone to vitamin K epoxide at the same time
Implementation Method 2
Vitamin K undergoes electron reduction to a reduced form of vitamin K (called vitamin K hydroquinone) by the enzyme vitamin K epoxide reductase (VKOR). Vitamin K epoxide is then re-converted to vitamin K by the vitamin K epoxide reductase
Data Source
AI summary
The invention encompasses the use of one or more compounds selected from a list comprising i) reduced forms of vitamin K and/or ii) reduced forms of a vitamin K analog and/or iii) reduced forms of a vitamin K precursor for the expression of one or more functional vitamin K-dependent proteins in cell culture as well as processes for the fermentation of eucaryotic cells expressing one or more vitamin K-dependent proteins wherein one or more compounds selected from a list comprising i) reduced forms of vitamin K and/or ii) reduced forms of a vitamin K analog and/or iii) reduced forms of a vitamin K precursor are added to the cell culture medium before and/or during the fermentation process.