Protein expression services: how a protein expression service and a custom protein expression project are scoped and staged, and what a protein expression company should carry the risk for

Staging the project

1. Feasibility before production. A short feasibility stage tests expression and solubility in a small number of constructs and hosts and ends with a decision rather than a delivery. It is the cheapest information you will buy on the project, and a provider unwilling to sell one is a provider proposing you fund their risk.
2. Construct and host screening. Screening varies the boundaries, the tag, the fusion partner and the host in parallel. The value is in breadth rather than depth, so ask how many variants the screen actually covers and how a winner is chosen, because a screen of two is not a screen.
3. Scale-up is a separate decision. What works in a small culture does not always survive scale-up, and a provider should say so. Price scale-up as its own stage with its own acceptance criteria rather than assuming the feasibility yield holds.
4. Cell bank and material ownership. Settle who owns the construct, the cell bank and the process, and where they are stored. A programme that will re-order should hold or be able to obtain the bank, or the second batch is a negotiation from a weak position.
5. Acceptance criteria in the contract. Write the quantity, the purity method and threshold, the activity assay and the endotoxin limit into the agreement. Acceptance disputes in this category are almost always about criteria that were discussed and never written down.

What a provider should carry, and what you should

A provider should carry execution risk: that the agreed process was run competently, the analytics were performed, and the material meets the written specification. You carry biology risk: that this protein can be made in this system at all.

Contracts that try to move biology risk to the provider are priced accordingly, and the premium is usually larger than the cost of a staged approach that finds the problem early.

Comparing quotes that look different

Providers quote by stage, by milestone or per unit of delivered protein, and the three are not comparable until you normalise them against the same specification and the same stop points. Ask each to price your own staging rather than presenting theirs.

Ask what happens if feasibility fails. A provider whose answer is clear and whose charge for that outcome is modest is telling you they expect to find out early, which is what you want.

Common questions

What does a protein expression service include?

Typically construct design and synthesis, transformation or transfection, small-scale expression and solubility screening, scale-up, purification and the agreed analytics, delivered against a written specification.

How long does a protein expression project take?

It depends on the host and whether the protein expresses at all. Bacterial projects on a well-behaved target are short; mammalian expression, difficult targets and anything needing a stable line take substantially longer. Stage the contract so you learn which you have early.

Should I pay a fixed price or by stage?

By stage for anything uncertain. A fixed price for a difficult protein means the provider has priced the risk of failure into your quote whether or not it happens.

Who owns the cell bank?

Whatever the contract says, so read it. If you expect to re-order, ensure you own or can obtain the bank and the process description, otherwise the second batch is a sole-source negotiation.

Browse by service class

• Compare Gene synthesis on advertised prices