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<h2 data-section-id="pdko8n" data-start="0" data-end="50">What are recombinant proteins for cell culture?</h2>
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Recombinant proteins for cell culture are biologically active growth factors, cytokines, and signaling molecules produced using recombinant DNA technology to control specific cellular functions in vitro. Growth factors such as FGF (fibroblast growth factor), EGF (epidermal growth factor), and TGF-&beta; (transforming growth factor beta) regulate cell growth, proliferation, survival, and differentiation. Cytokines including IL-2, IL-7, IL-15, and IL-21 influence immune cell activation, expansion, and function. These proteins are widely used in serum-free and chemically defined media, stem cell and iPSC culture, immune cell expansion, organoid development, hybridoma production, and cell and gene therapy workflows where precise control over cellular signaling is required.
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<h2 dir="ltr">What you will find:</h2>
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<ul>
<li>Includes cytokines, chemokines, growth factors, and signaling proteins to support proliferation, differentiation, and maintenance of&nbsp;mammalian cells</li>
<li>Rat, human, and mouse recombinant proteins compatible with translational research models and diverse mammalian cell culture&nbsp;</li>
<li>Optimizing cell metabolic activity, signalling pathways, and experimental reproducibility in vitro using recombinant proteins&nbsp;</li>
<li>Suitable for organoid development, expansion of cells, activation of immune cells, neuronal studies, and protein expression workflow optimization.</li>
</ul>
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<h2 data-section-id="4x59d8" data-start="1050" data-end="1118">How to choose recombinant proteins, cytokines, and growth factors</h2>
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Quality grade: RUO vs. preclinical vs. GMP
Research-use-only (RUO) proteins are suitable for most academic and industrial research applications. Preclinical-grade proteins provide enhanced documentation and quality control for studies supporting clinical development. GMP-grade proteins are manufactured under controlled quality systems with complete traceability and lot-to-lot bioactivity verification, making them appropriate for cell therapy, gene therapy, and other regulated applications.
Expression system and post-translational modifications
The production system can significantly affect protein activity. HEK293 and other mammalian expression systems preserve native human post-translational modifications such as glycosylation and phosphorylation, which are often necessary for full biological function. Bacterial expression systems such as E. coli may offer lower cost and higher yields but cannot reproduce many of these modifications.
Carrier-free formulation
Carrier-free recombinant proteins are formulated without stabilizing proteins such as bovine serum albumin (BSA). This eliminates potential experimental interference from carrier proteins and supports serum-free, animal-component-free, and GMP-compatible workflows. Carrier-free formulations are especially important when studying sensitive signaling pathways or developing clinical manufacturing processes.
Endotoxin level and purity
Endotoxins can stimulate inflammatory responses and alter cell behavior, particularly in immune cell cultures. For T-cell expansion, stem cell culture, and other sensitive applications, low-endotoxin or endotoxin-free proteins with documented purity above 95% are preferred to ensure reproducible results.
Stability format: standard vs. thermostable
Standard recombinant proteins gradually lose activity during prolonged incubation at 37&deg;C. Thermostable variants, such as engineered FGF2 formulations, maintain biological activity for longer periods and reduce the need for frequent media supplementation. These products can improve workflow efficiency in stem cell maintenance and differentiation protocols.
Storage and reconstitution
Lyophilized recombinant proteins offer extended shelf life and are typically stored frozen until use. After reconstitution, proteins should be aliquoted into single-use portions whenever possible to minimize repeated freeze-thaw cycles that can reduce activity. Proper storage conditions vary by product and should follow the manufacturer's recommendations.
<h2 data-section-id="rxnuuy" data-start="3659" data-end="3704">&nbsp;</h2>
<h2 data-section-id="1fljvas" data-start="4451" data-end="4476">Specifications context</h2>
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Modern recombinant cytokines and growth factors are available in a wide range of formats including carrier-free, low-endotoxin, animal-component-free, and GMP-grade formulations. Many GMP-grade cytokines such as IL-2, IL-7, IL-15, and IL-21 undergo lot-specific bioactivity testing using validated reference standards to ensure consistent biological performance. Mammalian-cell-expressed proteins are increasingly preferred for applications requiring native structure and maximum biological activity.
As of 2026, carrier-free, low-endotoxin recombinant proteins produced in mammalian expression systems have become the preferred choice for stem cell culture, immune cell expansion, organoid development, and advanced biomanufacturing workflows.
For basal media used alongside recombinant proteins, see Classic Media. For additional supplementation reagents, see Cell Culture Supplements &amp; Additives. Browse Mammalian Cell Culture for the broader category.
<a href="https://mbpinc.net/contact-us">Contact the expert team</a> at MBP today and get optimized recombinant proteins for your lab.

Recombinant Proteins

MSDS

Growth Factor-eFlyer

Growth Factors and Cytokines-Brochure

Growth Factors and Cytokines-FAQ

Role of Growth Factors in Cell Differentiation-Poster

Recombinant Human FGF23

Z100985 by Applied Biological Materials is recombinant human FGF23 (Fibroblast Growth Factor 23), expressed in E. coli and purified to >95% by SDS-PAGE. This 23 kDa phosphotropic hormone has an ED50 of &lt;0.3 µg/mL in 3T3 cell proliferation assays and a specific activity of 3.0 × 10⁴ units/mg. Endotoxin &lt;1.0 EU/µg; lyophilized from PBS pH 7.4.

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Recombinant Human FGF23, 20 µg

Recombinant Human FGF23, 1.0 mg

Recombinant Human FGF3

Z102285 by Applied Biological Materials — recombinant human FGF3 (HBGF-3/INT2), E. coli, 21.2 kDa, tag-free, &gt;95% purity, ED50 &lt;5 ng/mL. For inner ear development, angiogenesis, and FGF receptor research.

Unit Quantity

Recombinant Human FGF4

Recombinant Human FGF4 (HST-1/K-FGF), catalog Z102605 by ABM. E. coli-expressed, 20 kDa, >95% purity, lyophilized. Bioactive with ED50 &lt;0.2 ng/mL. Heparin-binding FGF-family mitogen. Endotoxin &lt;1.0 EU/µg.

Recombinant Human FGF4, 25 µg

Recombinant Human FGF4, 100 µg

Recombinant Human FGF4, 1.0 mg

Recombinant Human FGF6, 25 ug

Recombinant Human FGF6 (HBGF-6), catalog Z101685 by ABM. E. coli-expressed, 19 kDa, >95% purity, lyophilized, 25 µg. Muscle-enriched FGFR1/FGFR2 ligand for myoblast and regeneration research. Endotoxin &lt;1.0 EU/µg.

Recombinant Human FGF8

Recombinant Human FGF8 isoform 8B (Z101705) by ABM — 22.5 kDa E. coli-expressed, >95% pure, ED50 0.05–0.5 ng/mL, Kallmann syndrome-linked. Order from MBP INC.

Recombinant Human FGF8, 50 µg

Recombinant Human FGF8, 1.0 mg

Flyer

Brochure

Recombinant Human FGF9

Z100215 by ABM is recombinant human FGF9 expressed in E. coli, &gt;95% purity by SDS-PAGE, 23 kDa, lyophilized. ED50 ~5 ng/mL in 3T3 cell bioassay. For research use only.

Recombinant Human FGF9, 20 µg

Recombinant Human FGF9, 1.0 mg

Recombinant Human FLT3 Ligand (FLT3LG)

Recombinant Human FLT3 Ligand (Z100225) by ABM is a >95% pure, E. coli-expressed, non-glycosylated FLT3LG protein with an ED50 of ~1.0 ng/mL in AML5 cell proliferation, cross-reactive with mouse Flt-3, and supplied lyophilized in PBS pH 7.0 with <1.0 EU/µg endotoxin.

Recombinant Human FLT3 Ligand (FLT3LG), 10 µg

Recombinant Human FLT3 Ligand (FLT3LG), 1.0 mg

Recombinant Human FSHB

Z100235 by Applied Biological Materials (ABM) is recombinant human FSHB (Follicle-Stimulating Hormone Beta subunit) expressed in CHO cells. Molecular weight 30 kDa; purity >95% by SDS-PAGE; specific activity 1.0 × 10⁴ IU/mg; endotoxin <1.0 EU/µg. Lyophilized. Available in 10 µg, 50 µg, and 1.0 mg sizes.

Recombinant Human FSHB, 10 µg

Recombinant Human FSHB, 1.0 mg

Recombinant Human Follistatin (FST)

Recombinant Human Follistatin (FST) Z101035 by ABM — E. coli-expressed, 31 kDa, ED50 0.1–0.4 µg/mL (Activin A neutralization). Activin and BMP antagonist for stem cell, reproductive biology, and TGF-β pathway research. 10 µg.

Recombinant Human Follistatin (FST), 10 µg

Recombinant Human Follistatin (FST), 1.0 mg

Recombinant Human Fractalkine  (CX3CL1)

Recombinant Human Fractalkine (CX3CL1) Z101895 by ABM — E. coli-expressed, 8.9 kDa, 20–100 ng/mL chemoattraction (BaF3/CX3CR1). For neuroinflammation, monocyte trafficking, and chemokine biology research. 20 µg or 1.0 mg.

Recombinant Human Fractalkine  (CX3CL1), 20 µg

Recombinant Human Fractalkine (CX3CL1), 1.0 mg

Recombinant Human G-CSF (CSF3)

Recombinant Human G-CSF CSF3 (Z100245) by ABM is a tag-free, E. coli-expressed lyophilized cytokine, 19 kDa, >95% pure, endotoxin &lt;1.0 EU/µg, ED50 ≤5 ng/mL, with confirmed cross-reactivity to human and mouse cells.

Recombinant Human G-CSF (CSF3), 10 µg

Recombinant Human G-CSF (CSF3), 50 µg

Recombinant Human GDF3

Z101735 by ABM — Recombinant Human GDF3, 13 kDa, tag-free, expressed in E. coli. Purity &gt;95% by SDS-PAGE, endotoxin &lt;1.0 EU/µg, Smad2 phosphorylation confirmed. Reconstitute in 100 mM Acetate pH 4. Available in 20 µg and 1.0 mg.