For novel drug development.

Design and manufacturing of high-quality and bioactive recombinant proteins.

We are a quality-focused biotechnology company dedicated to enhancing the latest therapeutic technologies, including cell therapies, gene editing, immunotechnology, and vaccines.

Innovative drug discovery requires innovative reagents.
Our customers develop novel therapies and so they need customized or first-to-market proteins and enzymes.

We carefully select our catalog products based on unmet needs in the market.

Our focus is customization and tailored solutions so that your innovation potential is limitless.

Your centralized source for quality recombinant proteins and enzymes.


Comprehensive catalog where versatility meets quality.

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.

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

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.

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.

Reliable and bioactive commercial proteins are fundamental to successful and timely drug development.


Structure Aided Design & Multiplex Screening

Researchers face common challenges when using recombinant proteins including:

  • Membrane protein antigen production
  • Recombinant antigen immunogenicity
  • Antibody affinity
  • Batch-to-batch consistency
  • Production time & production cos

SAMS (Structure Aided Design and Multiplex Screening) is our high-throughput protein expression and purification screening system.

The structural hierarchy is the overarching list of variables that will affect protein structure and function.

Unmet needs for commercial proteins are identified via literature and database searches. We then use bioinformatics and structural analysis to design a variety of protein sequences/structures based on variables from the structural hierarchy.

Integrity, signal peptide, codons, etc. are analyzed using structural informatics and 3D modeling to determine how they will influence all four levels of protein structure.

The optimal protein configuration is identified from large search spaces of protein configurations and expression conditions. We prioritize natural protein configuration, yield, and bioactivity.

Protein designs are tested for bioactivity in multiple cell types/settings. Because we ensure protein function in multiple settings, you can be confident that the protein you purchase will work for your application.

Advantages of SAMS Platform

Success with SAMS

Our products are used worldwide for diverse applications, including basic research, drug discovery, diagnostic study, antibody production, quality control testing, and more. Through the SAMS platform, we have already produced multiple challenging proteins, including the first ever full-length Claudin 18.2 protein.

Drug development is full of unknowns. Don’t let your reagents be one of them.

Quality Control & Assurance

At KACTUS, we focus on quality at every step of the process, from protein engineering to manufacturing, so you can be confident in the products you receive.

KACTUS recombinant proteins are designed and manufactured in-house, giving a high level of control over every step from protein engineering to product validation. We test each prodcut for bioactivity throughout the development process to ensure function in multiple in vitro settings. Each batch undergoes strict quality control testing including purity, activity, and endotoxin. Our high level of control results in superior batch to batch consistency. Moreover, the majority of our products are expressed using mammalian cell lines, allowing for post-translational modification, native protein conformation, and low endotoxin levels.

Vertical integration of protein engineering & manufacturing

Mammalian cell line expression systems

Comprehensive quality control testing

Quality Control

Quality control is a critical aspect of recombinant protein production that ensures the purity, potency, and consistency of the final product. Our quality control systems are designed to monitor and assess the quality of the production process and final product.


Process Validation

We monitor the entire production process to ensure expression conditions are optimal for that specific protein. This includes monitoring the growth of the host cells, expression of the target gene, and purification of the recombinant protein. The expression process is optimized to minimize the presence of contaminants that can affect the purity or activity of the final product.

Analytical Testing

PURITY The purity of each recombinant protein is ensured using HPLC and by quantifying the level of impurities, such as host cell proteins, endotoxin, and host cell DNA in the final product.

ACTIVITY The potency of our recombinant proteins is analyzed by measuring its in vitro activity, such as its ability to bind to its target molecule via ELISA or SPR assay.

CONSISTENCY Our products are tested for batch-to-batch consistency to ensure stable bioactivity across lots. Additionally, we assess stability of our products by measuring degradation over time and resistance to environmental stress factors, such as temperature and pH changes.

Batch to Batch Consistency

Fig 1. Imobilized Human DDL3, His Tag at 0.1µg/mL (100µl/well) on the plate. Dose response curve for Anti-DDL3 Antibody, hFc Tag with an EC50 of 5.0, 4.5 and 5.0 ng/mL respectively determined by ELISA

Fig 2. Immobilized Human Siglec-10, His Tag at 0.5µg/mL (100µl/well) Dose response curve for Anti-Siglec-10 Ab., hFc Tag with an EC50 OF 7.3, 7.7 and 7.4ng/mL, respectively asgetermined by ELISA

Fig 3. Immobilized Human CD4 at 0.5µg/mL (100µl/well) on the plate. Dose response curve for Anti-CD4 Antibody, hFc Tag with an EC50 OF 10.2, 10.6 and 10.6 ng/mL respectively as determined by ELISA

Quality Assurance

Our quality management system monitors the entire production process to ensure each batch is manufactured under the same optimal conditions for that protein. This includes monitoring the growth of the host cells, expression of the target gene, and purification of the recombinant protein. Moreover, the protein expression process is optimized during development to minimize the presence of contaminants that can affect the purity or activity of the final product.

Trending Products

VLP-Displayed Antigens

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


Browse our suite of HLA-G monomers and tetramers and associated LILRA and LILRB receptors.

Recombinant Laminin 521

Cell adhesion protein for iPSC culture and other pluripotent stem cells.

Reliable bulk supply of research-grade or preclinical-grade.

AAV Titer ELISA Kits

High sensitivity, reproducible AAV Capsid Titer using sandwich ELISA.

Bioactive CD3 Proteins

High-purity, bioactive CD3 proteins for bispecific antibody development.

Monomers & heterodimers with equally expressed subunits.

Product Literature

GMP-Grade RNA Enzymes

GMP-Grade Enzymes for mRNA Production Restriction Enzymes, In Vitro Transcription, Capping, Tailing, Circularization ProductsT7 RNA Polymerase (GMP-Grade)Pyrophosphatase, Inorganic (GMP-Grade)RNase RT4 Read More...

Gene Editing Reagents

Explore our GMP-Grade CRISPR Cas9, Cas12a, MaxNuclease, AAV ELISA Kits, and DNA Amplification Enzymes ProductsAccuBase™ Base Editor, GMP-GradeAccuBase™ Base Editor, Read More...

Recombinant Proteins

Comprehensive portfolio of target proteins designed for every stage of antibody drug discovery campaigns ProductsFc ReceptorsCD3 ProteinsFGFRsCD47 & SIRPVLP-Displayed Antigens Read More...

Cell Therapy Proteins

MHC Complexes, CAR-T Targets, VLPs, Cytokines, and Laminin 521 ProductsCAR-T TargetsCytokinesSoluble TCR Expression ServicesMHC Tetramers & MonomersPeptide-ready MHCsHLA-G and LILRsLaminin Read More...

Base editing technology leads a new chapter in drug development

View All Products Since its debut in 2016, base editing technology has opened up new perspectives and methods for drug Read More...

MSLN Targeted Drugs Entering the Fast Lane

View All Products Since December 2023, there have been several positive updates about drugs targeting MSLN. On December 19th, RemeGen Read More...

Exploring the Role of MICA in Tumor Immunity and Targeted Therapies

Contact UsView All Products MICA, also known as MHC Class I Polypeptide-Related Sequence A, is a type I MHC molecule Read More...

New advances in CRISPR gene therapy drugs

Contact UsView All Products On April 3, 2023, Vertex Pharmaceuticals and CRISPR Therapeutics announced the completion of the rolling biologics Read More...

Potential Immunotherapy Target TM4SF1

Contact Us View All Products TM4SF1 (Transmembrane 4L six family member 1) is a member of the TM4SF subfamily in Read More...

CDH17: A Safe CAR-T Target for Treatment of Solid Tumors

Contact Us View All Products Chimeric antigen receptor T cell (CAR-T) therapy has been successful in the field of hematological Read More...

GDF15-GFRAL breaks into the new drug track

Contact UsView All Products A variety of metabolic diseases that plague today's society, such as obesity, diabetes, cancer, etc., have Read More...

The culprit of cancer metastasis – uPAR-uPA

Contact UsView All Products Tumor invasion and metastasis are key risk factors for tumor recurrence and patient death. Tumor invasion Read More...