TurboCHO™ Protein Expression Kit

TurboCHO™ has shown consistent performance from plate formats through shake flasks, and no additional adjustments have been required during scale-up at these volumes.

The culture parameters are also consistent across different shake flask sizes, from 125 mL to 5 L Erlenmeyer flasks. We recommend maintaining a working volume of 20–33% of flask capacity, or following the manufacturer’s recommended working volume.

Wave/reactor scale data is still being generated, and optimized recommendations will be shared once validation is complete.

For our control molecules, harvest viability typically ranges from approximately 75% to 91%, with the majority of runs above 85%.

We do not recommend reducing the plasmid amount, as the protocol is optimized around the specified DNA level. For reliable and consistent expression, we suggest following the recommended amount in the protocol. Potentially, 1 μg/mL target DNA supplemented with 1.5 μg/mL filler DNA may achieve comparable results.

We are still collecting broader data on side-product profiles for bispecific antibodies and complex modalities. Early observations are promising, but additional data is needed before we can claim a clear advantage.

TurboCHO™ shows no unusual glycan patterns compared with other transient CHO systems. Current data is consistent with standard CHO glycan profiles, and available datasets can be shared upon request.

Our one-step purification recovery is typically approximately 55% to >70%, and data is on our customer-facing deck

TurboCHO™ cell maintenance can support up to 4-day subculture intervals.

Recommended seeding densities:

• 2-day post-subculture: 0.7–0.8 × 10⁶ viable cells/mL
• 3-day post-subculture: 0.3–0.35 × 10⁶ viable cells/mL
• 4-day post-subculture: 0.12–0.15 × 10⁶ viable cells/mL

We recommend that post-thaw viability exceed 90%.

If viability is between 80% and 90%, cells may be cultured for up to an additional 3 days to reach the desired viability.

If viability is below 80%, we recommend thawing an additional vial of cells.

In our evaluations, cell viability is generally similar between spin-down and non-spin workflows. The primary factor driving yield differences is cell density and medium freshness during transfection.

At the same nominal transfection density, the spin-down workflow consistently delivers higher titers because resuspending cells in fresh medium creates a cleaner environment for DNA–reagent uptake.

We recommend using non-baffled flasks for the TurboCHO™ CHO-K1–based system.

While baffled flasks can improve titers in some CHO-S systems by enhancing oxygen transfer, we do not recommend them for TurboCHO™, particularly for protein-based or bispecific molecules. Increased shear stress in baffled systems may contribute to protein fragmentation and reduced purity. Excessive foaming may also interfere with magnetic bead purification and reduce recovery.

TurboCHO™ does not have the same oxygen transfer limitations as CHO-S systems, so the risks outweigh the benefits.

In general, no significant performance differences have been observed between Erlenmeyer and Thomson flasks under standard conditions. Customers may evaluate based on their specific equipment setup if needed.

Performance depends on the vector backbone. The best performance is achieved with the pTT5 vector.

We have only observed a performance decrease with pcDNA3.4, while other backbones should be evaluated case-by-case.

We recommend pTT5 primarily due to its higher expression performance.

Compared with pcDNA3.4, pTT5 also offers:

• Improved expression stability
• Higher transfection efficiency
• Better metabolic efficiency in host cells

Overall, this results in higher protein yield and more consistent performance.

Yes. We can support both in-house subcloning guidance and full-service solutions.

For customers transitioning from pcDNA3.4 to pTT5, both restriction-based and seamless cloning methods are viable. The vectors share common restriction sites including XbaI, BamHI, and HindIII, enabling straightforward subcloning.

Gene synthesis services can also be provided.

Yes. The transfection reagent is proprietary and developed by GenScript R&D. It is a chemically based transfection reagent formulated specifically for TurboCHO™.

Yes. Mycoplasma testing is included in the Certificate of Analysis (CoA).

We have not observed any abnormal endogenous protease activity in the cell line, and no target protein fragmentation issues have been detected so far.

TurboCHO™ medium contains 8 mM L-Alanyl-L-Glutamine.