Comprehensive catalog where versatility meets quality.

2500+ Catalog Products

Choose from our selection of over 2500 ready-to-ship recombinant protein products. Our catalog products are carefully selected based on product quality and unmet needs in the research industry.

Tailored Expression Systems

We test all of our proteins in 8-16 various expression conditions to determine the optimal expression conditions for yield, purity, and activity.

High-Purity & Bioactivity

Our products undergo rigorous quality control testing for purity and bioactivity. We use analyses such as HPLC, SPR, and ELISA to ensure suitability for your application.

Protein Structure Design & Engineering

Rational, thoughtful decisions based on structural analysis are the foundation for our SAMS protein engineering platform. All of our catalog products undergo rigorous design testing to ensure natural protein configurations and optimized activity.


MHC Products & Services

MHC Monomers & Tetramers

150+ catalog products with various alleles, peptides, fluorophores, & tetramers.

Peptide-Ready MHCs

Stabilized peptide-free MHCs designed for loading your neoantigen peptides in-house.

Soluble TCR Expression

Custom expression of soluble TCRs and MHC/TCR binding analysis.

Browse Products by Application:

Trending Products

VLP-Displayed Antigens

Full-length multi-pass transmembrane proteins for antibody drug discovery and development.


GMP-Grade Enzymes

For your clinical and commercial manufacturing.

With a full portfolio of mRNA production enzymes and gene editing enzymes, KACTUS accelerates your transition from preclinical studies to commercial manufacturing, ensuring a seamless and efficient pathway to market readiness.

FDA Drug Master File Submission

ISO13485 Certification

Popular Products


Immune Checkpoint Proteins


Transforming Growth Factors

Custom Protein Production

Custom recombinant protein expression with optimized activity and difficult-to-express targets.

Using our SAMS Technology platform, KACTUS specializes in protein engineering and expression optimization tailored for both routine and difficult-to-express proteins. Our diverse range of expression systems includes HEK293, CHO, E. coli, and yeast cells. Customization is at the heart of our service. Whether you require specific tags, fluorescent labels, or biotinylation, we're equipped to cater to your specific experimental needs. Our scientific team will assist you with protein structure optimization specific to your application.

Bioactive proteins

Choice of expression system

High Purity

Large Scale Production


Empowering Novel Drug Development

→ Carefully selected catalog products based on unmet market needs
→ Customization options to meet innovative drug development demands
→ Large and continuously expanding catalog

SAMS™ Protein Engineering Platform

→ Structure Aided Design and Multiplex Screening (SAMS) 
→ Optimized protein sequence and 3D structure
→ Expression condition testing specific to each product and cell line

Quality Control

→ Tested for purity and bioactivity
→ Control over endotoxin, host cell protein, & other contaminants
→ Comprehensive suite of analytical equipment including SPR, HPLC, Mass Spec, etc.

Our Valued Partners

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Events & News

Inflammatory Target: TSLP

Inflammatory Target: TSLP

Thymic Stromal Lymphopoietin (TSLP), is a pleiotropic cytokine of the IL-2 family, closely related to IL-7, playing a significant role in immune r...

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