Yeast Expression System

The yeast protein expression system is a cost-effective eukaryotic expression platform capable of both extracellular secretion and intracellular expression. Exogenous genes expressed in yeast undergo essential post-translational processing, resulting in properly folded proteins with authentic glycosylation modifications.

These proteins exhibit significantly greater structural stability compared to those expressed in prokaryotic systems, making the yeast host particularly suitable for expressing complex eukaryotic genes and producing functional therapeutic targets. In yeast secretion expression, target proteins are secreted directly into the extracellular matrix, facilitating streamlined purification and high protein recovery.

Service Process & Deliverables

1. Expression Vector Construction

15 – 20 Days

Workflow Process

• Target sequence codon optimization and custom gene synthesis
• PCR amplification product ligation into yeast expression vectors (pPIC9K, pPIC3.5K, pPICZαA, etc.)
• Transformation into E. coli cloning hosts and positive colony screening
• Sequence verification to deliver sequence-confirmed recombinant plasmids

Key Feature

Vector Optimization: To enhance expression success and achieve higher yields, we offer custom C-terminal fusion tag configurations alongside conventional N-terminal tags.

2. Transformation & Strain ID

10 – 15 Days

Workflow Process

• Large-scale preparation and linearization of transfection-grade recombinant plasmids
• Electroporation transformation into yeast host strains (GS115, X-33, KM71, etc.)
• PCR verification of successful genome integration and recombinant transformants
• Multi-copy antibiotic screening (using G418, Zeocin, etc.) to isolate high-copy expressor clones

3. Scale-Up & Purification

10 – 15 Days

Workflow Process

• Small-scale expression screening across 20 to 40 candidate strains
• Selection of the optimal high-yielding strain and induction parameter optimization
• Large-scale fermentation culture expansion and target protein purification

Key Feature

Multiple Purification Strategies: We explore various chromatographic conditions—including affinity, ion-exchange, hydrophobic interaction, and gel filtration—to establish the optimal purification scheme for your target.

4. Optional Services

5 Days

Available Options

• Endotoxin removal (<0.1 EU/µg or <0.01 EU/µg thresholds)
• Aseptic processing, 0.22 µm filter sterilization, and custom aliquoting
• Lyophilization for extended shelf-life stability
• Enzymatic tag removal and cleavage (optional add-on)

Key Feature

Customers have the flexibility to select from a range of additional downstream services tailored to their specific analytical or therapeutic requirements.

5. QC & Release

5 Days

Workflow Process

• Purity determination via SDS-PAGE and HPLC (>85% to >98%)
• Accurate concentration quantification (BCA or A280 absorption)
• Optional SEC-MALS or bioactivity verification assays

Key Feature

Every delivered project includes a comprehensive Certificate of Analysis (COA) documenting experimental conditions and analytical QC chromatograms.

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