San Diego, California

Recombinant protein expression and purification services

VexisBio supports research protein projects from construct strategy and expression feasibility through purification, quality control, and assay-ready delivery. Programs are designed around the final use of the materialâ€”as an antigen, antibody-screening reagent, ELISA standard, control, enzyme, or research protein.

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Recombinant protein expression and purification services in San Diego

Recombinant protein services

Built around downstream assay use

Protein projects are scoped around the final decision the material must support: antibody screening, ELISA calibration, biomarker feasibility, reagent qualification, or partner-facing technical documentation.

Construct strategy

Domain, tag, cleavage, and expression-system planning for soluble, usable assay reagents.

Expression support

Small-scale expression feasibility and workflow planning for recombinant antigens and controls.

Purification workflow

Affinity purification and polishing strategy with attention to purity, yield, and formulation needs.

Assay-ready QC

Concentration, purity, identity, lot consistency, and fit-for-purpose documentation support.

Common starting points

Protein target, accession, or sequence
Species and domain boundaries
Desired tag, buffer, and purity target
Intended use as antigen, ELISA standard, calibrator, or control
Timeline, scale, and downstream assay plan

Best-fit projects

Research-use recombinant antigens, assay standards, controls, antibody-screening reagents, and protein materials that need to connect cleanly to ELISA or biomarker assay development.

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Expression-system selection

The host is selected according to protein complexity, folding, post-translational modification, activity, scale, timeline, and downstream use. Final platform availability is confirmed during technical review.

Bacterial expression

E. coli workflows can be efficient for many soluble domains, antigens, enzymes, and proteins that do not require complex eukaryotic processing. Solubility, inclusion-body risk, tag strategy, and endotoxin requirements are considered early.

Baculovirus and insect cells

Insect-cell workflows may support eukaryotic folding, secretion, multimeric proteins, and targets that perform poorly in bacteria. A project may include bacmid or baculovirus generation, expression screening, and scale-up planning.

Mammalian expression

HEK293 or other mammalian workflows may be considered when secretion, disulfide formation, glycosylation, or mammalian-like processing is important.

Protein purification and quality control

Purification begins with the biochemical behavior of the target and its intended application. The scope may combine affinity capture, polishing, concentration, buffer exchange, tag removal, or refolding assessment with agreed analytical evidence.

Purification options

Affinity capture based on tag or protein properties
Ion-exchange or size-based polishing when appropriate
Tag cleavage and removal planning
Buffer exchange, desalting, and concentration
Refolding evaluation for insoluble material

Analytical QC

Protein concentration
SDS-PAGE purity assessment
Western blot identity support
Aggregation review when needed
Endotoxin testing by agreed method

Application readiness

ELISA standard or calibrator suitability
Antibody binding or screening support
Target-specific activity testing
Aliquoting and storage planning
Research report and lot documentation

Stage the work before scale-up

Stage	Typical work	Output
Sequence and use review	Review the target, construct, amount, purity, activity, formulation, and application.	Recommended construct, host strategy, and scope.
Expression feasibility	Evaluate expression, solubility, secretion, recovery, and preliminary purification behavior.	Feasibility results and a go, revise, or alternate-host recommendation.
Purification development	Establish capture, wash, elution, polishing, concentration, and buffer conditions.	Purified pilot material and preliminary QC.
Production and delivery	Scale the agreed workflow, perform contracted testing, formulate, aliquot, and document.	Research-use protein, QC package, and storage guidance.

Information needed for a quote

Protein name, sequence, accession, or plasmid map
Desired domain, tag, construct, or host
Target amount, concentration, purity, and buffer
Endotoxin or other critical quality requirement
Intended use and functional test
Available starting material and timeline

Typical deliverables

Construct and expression recommendation
Feasibility or expression-screen data
Purified research-use protein
Agreed concentration, purity, and identity results
Buffer, formulation, and storage information
Technical report with limitations and next steps

GMP, clinical-grade, or regulated production is not implied unless separately scoped and contracted.

Related service paths

Protein work often becomes most valuable when it is connected to upstream nucleic acids, antibody pairing, ELISA development, and validation planning.