ARCHIVED - NRC Scientists Develop Certified Reference Material for Popular Mineral Supplement with Cancer Prevention Potential

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September 05, 2005— Ottawa, Ontario

A multi-year research collaboration between NRC and Montréal's Institut Rosell-Lallemand has produced high-quality, measurement standards for one of the world's most commonly used mineral supplements, selenium enriched yeast. Up until now, a lack of reliable measurement techniques for determining the amount of a specific amino acid (selenomethionine) in selenized yeast has limited manufacturing improvements and fostered trade barriers.

To help get beyond these obstacles, Dr. Zoltan Mester and his research team within the Chemical Metrology Group of NRC Institute for National Measurement Standards (NRC-INMS) collaborated with Dr. John Kelly from the Proteomics Facility at the NRC Institute for Biological Sciences (NRC-IBS), and the Montréal-based biotech firm Institut Rosell-Lallemand. Together they developed detection methods for selenomethionine and produced a new Certified Reference Material (CRM) for selenium enriched yeast.

Why selenized yeast?

Selenium enriched yeast
Selenium enriched yeast

Selenium is one of the most commonly used mineral supplements and is touted for its role in cancer prevention and the mitigation of oxidative stress. It is recognized that various organoselenium compounds are more effective in this role than inorganic selenium salts. It has been known for decades that yeast (Saccharomyces cerevisiae) is able to accumulate large quantities of inorganic selenium and convert it to organic selenium compounds such as the non-canonical amino acid, selenomethionine. Consequently, yeast based selenium supplementation for both human nutrition and animal feed is widespread throughout the globe.

What is a CRM?

CRMs are used as part of every chemical measurement protocol for the evaluation of measurement precision and the calibration of analytical instruments. The concentration values assigned to the CRM by the producer, such as NRC-INMS, are invariant to time and space, and if all is working correctly in the analysts' laboratory these values will be faithfully reproduced. Such consistency permits measurements in one laboratory to be reliably compared to those in another laboratory, imparting traceability to the measurement. Analysts regard CRMs as the gold standard by which the reliability of their results is authenticated.

Unfortunately, the lack of reliable measurement techniques for determining the amount of selenomethionine in selenized yeast has hindered technical improvements in production, and created trade barriers. It is difficult if not impossible for manufacturers to move products across international boarders without full characterization.

NRC-INMS scientists, in collaboration with one of the largest yeast producers in the world, the Montreal-based biotech firm Institut Rosell-Lallemand, have developed ultrasensitive mass spectrometry-based detection methods for selenomethionine. Using these advanced measurement tools, a CRM for selenomethionine in yeast was produced. Institut Rosell-Lallemand, which has a significant economic stake in this work, made a substantial financial contribution to this research effort.

"The work that was achieved through our collaboration with Dr. Mester of the NRC in Ottawa has provided significant insight into the nature of our product. This knowledge has been beneficial from a marketing and regulatory point of view. Our increased understanding of our product through Dr. Mester's investigations has helped us maintain our role as scientific leaders in our industry."

Thomas A. Tompkins, Ph.D., Biochemistry and Microbiology Research Director, Institut Rosell-Lallemand

Illustration depicts a 3D model of the yeast enolase protein, showing three areas of selenomethionine incorporation (red dots). Image reproduced by permission of Zoltan Mester and The Royal Society of Chemistry from The Analyst, 2005, 130, (1), cover page.
Illustration depicts a 3D model of the yeast enolase protein, showing three areas of selenomethionine incorporation (red dots). Image reproduced by permission of Zoltan Mester and The Royal Society of Chemistry from The Analyst, 2005, 130, (1), cover page.

During the multi-year research project, a highly reliable measurement of selenomethionine in yeast was achieved as well as a full characterization of the selenized yeast material. As with any research, it was not without surprises. Dr. Mester's team from NRC-INMS in collaboration with Dr. John Kelly from NRC-IBS provided the first hard evidence for the massive incorporation of selenomethionine into the yeast proteome. They found that one out of three methionines (sulphur containing amino acids) was converted by the yeast to the organic selenium compound. These findings were featured on the cover page of the prestigious analytical chemical journal The Analyst published by the Royal Society of Chemistry.

Research Impacts

  • Consumer confidence — currently, it is difficult for the end user to determine the kind and amount of selenium present in dietary supplements.
  • This project exemplifies how metrology, the science of measurement, fosters the growth of Canadian industry and trade, and how technology know-how is transferred from a Government research organization into an industrial setting. Institut Rosell-Lallemand is now able to fully characterize their products and link the results of their measurements to international measurement standards thereby promoting their international trade efforts.
  • Financial contributions from the industry partner allowed two postdoctoral fellows to be trained in state-of-the-art mass spectrometry in the NRC Chemical Metrology Laboratory.
  • Horizontal collaboration, between two NRC institutes (NRC-INMS and NRC-IBS) that share complimentary mass spectrometry expertise, produced serendipitous results worthy of The Analyst cover page and caption (Zoltan Mester et al, Selenomethionine identification in yeast by 2D LC-MC based proteomics).

"Our collaboration is a good example of what can be achieved when groups with different backgrounds and from different NRC institutes work together to achieve something that neither could do on their own. This successful endeavour was scientifically interesting and produced a product that will have a positive impact on the Canadian health industry."

Dr. John Kelly, Associate Research Officer, Genomics and Proteomics, NRC Institute for Biological Sciences

Enquiries: Media relations
National Research Council of Canada

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