How ProPure Stops Endotoxin From Interfering With Your Research
Scientist
on
July 29, 2025
This blog post was written by Sino Biological, an innovative provider of bioreagents, empowering research with extensive catalog products, global client network and successful CRO projects. Their services are available on the Scientist.com marketplace.
Endotoxin (LPS) is known to induce systemic and neuroinflammatory responses in animals, which can complicate experimental results and potentially invalidate preclinical data. Also, recombinant proteins contaminated with endotoxins may adversely affect cellular behavior due to their immunostimulatory and cytotoxic properties.
To help researchers avoid these pitfalls and achieve reproducible results, we created ProPure™, a new line of endotoxin-free proteins to ensure accuracy and consistency of your experimental data. These high-quality recombinant proteins are all made in the USA and exclusively offered by Sino Biological.
Endotoxin: What it Is, and Why it Matters
Endotoxins, or lipopolysaccharides (LPS), are components of Gram-negative bacterial cell walls. They are highly stable, strongly adhesive to various surfaces and difficult to eliminate, even under high heat or extreme pH conditions.
Even trace amounts of endotoxin can trigger immune responses. In animal studies, endotoxins have been shown to elevate cytokine levels in both the blood and brain of rodent models, leading to systemic inflammatory immune responses. As a result, endotoxin contamination can significantly interfere with experimental outcomes, especially in immune-related or cytokine-sensitive assays.
Figure 1. Endotoxin induces increased IL-1β in both plasma and brain of rat models. Injection of 10 mg/kg.1
Moreover, endotoxins can induce protein aggregation and adversely affect protein stability and biological activity, both in vitro and in vivo. These effects introduce uncontrolled variables that compromise experimental reproducibility and obscure the true impact of your intended treatment or intervention.
Figure 2. Endotoxin induces protein aggregation both in vitro and in vivo.1,2
How does Sino Biological Guarantee Endotoxin-Free Protein Production?
At our Center for Bioprocessing (C4B) in Houston, Texas, we ensure endotoxin-free protein production at every step. Our facility does not conduct any E. coli-related experiments or manufacturing, which eliminates the primary source of endotoxin contamination. Instead of relying on endotoxin removal steps, we focus on preventing its introduction altogether.
We use endotoxin-free plasmids, pre-filtered buffers and low-endotoxin affinity plasticware throughout the production process. Final products are rigorously tested using the Limulus Amebocyte Lysate (LAL) assay and/or rFc-based assay to confirm minimal endotoxin levels.
In short, ProPureTM endotoxin-free proteins combine ultra-low endotoxin levels that exceed industry standards, with high purity, stability and lot-to-lot consistency, making them ideal for animal immunogenicity studies.