A new method for testing protein-based drugs

Researchers at the New Jersey Institute of Technology (NJIT) have unveiled a new lab technique that they say represents a "paradigm shift" in how pharmaceutical labs are testing and producing new protein-based drugs, such as therapeutic monoclonal antibodies being developed to treat a wide range of diseases, from cancer to infectious diseases
.

The researchers say the electrochemistry-based approach, which they describe in the journal Analytical Chemistry, can complete safety and quality testing
of emerging biological therapies in a fraction of the time it takes for traditional methods.

The study was conducted in collaboration with researchers at Merck, Johnson & Johnson and Ohio University, and received a $379,397 grant from the National Institutes of Health
.

"The approach we developed at New Jersey Tech has the potential to have a significant impact on quantitative proteomics, and it represents a paradigm shift in the pharmaceutical industry in monitoring biopharmaceutical products and process impurities for quality control," said
Hao Chen, the paper's corresponding author and professor in the Department of Chemical and Environmental Sciences at New Jersey Tech.

"With this study, we are now showing a way to quantify pharmaceutical product and process impurities
faster and more accurately than ever before.

Traditionally, this assay or protein quantification has involved the time-consuming preparation of synthetic isotope-labeled peptides that are used as internal standards for measuring total protein concentrations in samples, helping researchers actively monitor the effectiveness and safety
of therapeutic protein components throughout the drug development process.

To overcome this limitation, Chen's lab developed a Coulomb mass spectrometry (CMS) method that allows absolute quantification of proteins without the use of
standards.

"One can perform a CMS quantitative experiment immediately, rather than waiting weeks with traditional methods to get a standard or reagent
.

Ai Yongling, the paper's first author and a doctoral student at New York Institute of Technology, explains: "Such a device allows us to separate protein-digested peptides using liquid chromatography, monitor the oxidation of the peptide in an electrochemical flow cell to generate an electric current, and measure the oxidation rate
by mass spectrometry.

In their study, the team demonstrated their CMS method to achieve an absolutely quantitative mixture of multiple proteins (β-lactoglobulin B, α-whey protein and carbonic anhydrase) in a single run, without using any standards
.

Notably, the team also demonstrated the method's ability to detect protein deamides — degrading events
common in therapeutic proteins due to physical or chemical stress throughout the production and storage process.

The study's authors say the team successfully quantified the formation of several protein degradation products, including succinimide, a key intermediate in protein degradation, due to a lack of standards that had never been absolutely quantified
before.

"The lack of standards is caused by the challenge of synthesizing them from scratch," Chen said
.

Now, Chen's lab plans to apply their new method to large-scale quantification
of thousands of proteins at once.

Chen said: "Because proteins perform so many functions in living organisms, the importance of absolute protein quantification cannot be overemphasized
.

The study was funded by the National Institutes of Health (1R15GM137311-01) and also laid the groundwork
for a new project proposal recently funded by the National Science Foundation (ch-2203284).

Journal Reference:

1. Yongling Ai, Harsha P.
   Gunawardena, Xuanwen Li, Yong-Ick Kim, Howard D.
   Dewald, Hao Chen.
   Standard-Free Absolute Quantitation of Antibody Deamidation Degradation and Host Cell Proteins by Coulometric Mass Spectrometry.
   Analytical Chemistry, 2022; 94 (36): 12490 DOI: 10.
   1021/acs.
   analchem.
   2c02709ember 27, 2022).