Pyrosequencing Strengthens Intellectual Property for Core Technology With Two New U.S. Patents Issued.

Business Editors

UPPSALA, Sweden--(BUSINESS WIRE)--Aug. 28, 2001

Pyrosequencing AB (OMX:PYROa.) a developer, manufacturer and marketer of DNA sequencing systems for applied genetic analysis, today announced that it has been issued two additional U.S. patents covering the Company's Pyrosequencing(tm) Technology. U.S. Patent No. 6,210,891 and U.S. Patent No. 6,258,568 broadly cover methods for DNA sequencing based on the real-time detection of pyrophosphate and improvements in the chemistry of Pyrosequencing's novel genetic analysis technology. These patents complement and enhance the Company's existing broad coverage for sequencing-by-synthesis, an automated method for determining the base sequence of either DNA or RNA.

"These two new patents provide further protection for our unique chemistry and sequencing systems that are the essence of Pyrosequencing(tm)," said Erik Wallden, CEO and President of Pyrosequencing AB. "We now have strong coverage for our core technologies and are continuing to build value for our platform technology. In addition, we are developing new molecular diagnostic product concepts that leverage our intellectual property in cardiovascular and other therapeutic areas," he added.

U.S. Patent 6,210,891 covers methods for sequencing DNA, where the incorporation of bases (nucleotide triphosphates) is coupled to the release of pyrophosphate (PPi) and its detection via a light signal. PPi triggers a luciferin-luciferase based enzymatic cascade that produces a light pulse proportional to the amount of base incorporated. The sequencing or base incorporation reactions can be continuously monitored because the sequencing and detection are performed simultaneously as part of the same process.

The second patent (6,258,568) covers an improved DNA sequencing method that involves detecting pyrophosphate release as new nucleotides are added to a growing DNA strand and then degrading the unincorporated nucleotides through the addition of a nucleotide-degrading enzyme. In order to perform rapid and accurate sequencing without numerous wash steps, the unincorporated nucleotides must be removed before addition of the next nucleotides. The use of a nucleotide-degrading enzyme facilitates rapid, accurate and convenient sequencing without numerous wash steps. Additionally, the nucleotide-degrading enzyme switches off the light reaction and allows the next sequencing reaction to be initiated. The patent covers the removal of these excess nucleotides with enzymes, such as apyrase.

These new patents add to Pyrosequencing's strong intellectual property position surrounding sequencing and DNA analysis technologies, which includes a broad patent issued for sequencing-by-synthesis using any detection method. The sequencing-by-synthesis patent covers methods for determining the sequence of DNA or RNA molecules by detecting the incorporation or addition of specific nucleotides into a growing strand of DNA or RNA. Nucleotides are added, like building blocks, into the growing strand if they are complementary to the unpaired nucleotide that exists in the template strand. A polymerase enzyme helps add the nucleotides to this growing or newly synthesized strand of DNA or RNA and this incorporation can be detected using various methodologies.

About Pyrosequencing AB

Pyrosequencing AB develops, manufactures and sells complete solutions for applied genetic analysis based on its proprietary Pyrosequencing(tm) technology, a simple-to-use DNA sequencing technique. In the post-genome era, Pyrosequencing's technology has established the Company as one of the leading suppliers of solutions for accurate, consistent DNA analysis in research institutions and pharmaceutical, genomics and agbiotech companies.

For the analysis of single nucleotide polymorphisms (SNPs), the PSQ(tm)96 System with SNP Software and Reagent Kits is used by customers such as AstraZeneca, GlaxoSmithKline, the Harvard Center for Cancer Prevention, the National Institutes of Health (NIH), the Karolinska Institute and DuPont Agriculture. The Company's Sequence Analysis Software and Reagent Kits together with the PSQ 96 System are used for the identification of gene-specific DNA sequences for applications such as bacterial and viral typing where speed and ease of use are essential.

The Company is headquartered in Uppsala, Sweden with North American operations located in Westborough, Massachusetts. Pyrosequencing AB also has sales offices and distribution partners in Europe, Asia Pacific and the Middle East. Pyrosequencing AB is listed on the OM Stockholm Exchange. The Company's web address is www.pyrosequencing.com.

Certain statements in this press release are forward-looking. These may be identified by the use of forward-looking words or phrases such as "believe," "expect," "intend," and "should," among others. These forward- looking statements are based on Pyro-sequencing's current expectations. The Private Securities Litigation Reform Act of 1995 provides a "safe harbor" for such forward-looking statements. In order to comply with the terms of the safe harbor, Pyrosequencing notes that a variety of factors could cause actual results and experience to differ materially from the anticipated results or other expectations expressed in such forward- looking statements. Such uncertainties and risks include, but are not limited to, risks associated with management of growth and international operations (including the effects of currency fluctuations), variability of operating results, the commercial development of the DNA sequencing and genomics market, nucleic acid-based molecular diagnostics market, and genetic vaccination and gene therapy markets, competition, rapid or unexpected changes in technologies, fluctuations in demand for Pyrosequencing's products (including seasonal fluctuations), difficulties in successfully adapting the Company's products to integrated solutions and producing such products, and the Company's ability to identify and develop new products and to differentiate its products from competitors.

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