SGHL Signal Hill Acquisition Corporation

Invitrogen Corporation (Nasdaq:IVGN), a global leader in life sciences, and Sentigen Holding Corp. (Nasdaq:SGHL) today announced that they had entered into a definitive merger agreement under which Invitrogen will acquire New Jersey-based Sentigen in a cash transaction at a price of $3.37 per share, or approximately $25.9 million for all shares currently issued and outstanding. As of June 30, 2006, Sentigen had cash and cash investments on its books valued at approximately $11.7 million and debt of $0.8 million. Sentigen's proprietary Tango(TM) Assay System and division arrested Assay Ready Cells(TM) will bolster Invitrogen's leading position in assay development by providing a novel approach to screen G-protein coupled receptors (GPCR) and other key drug target classes, as well as providing a methodology to convert live cell assays into ready-to-use consumable products. Sentigen will become a part of Invitrogen's Discovery Sciences Business based in Madison, Wis. Tango(TM) assay technology provides a universal assay system for GPCR targets, the most screened target class in drug discovery. The Tango(TM) assay platform also has utility in measuring protein-protein interactions in living cells, which can be an important way to determine the function of a protein of interest. Sentigen's Assay Ready Cells(TM) technology is designed to improve the quality and consistency of cellular assays used in drug screening and reduce the need of our clients to engage in costly ongoing cell culture operations to support cell-based drug discovery, effectively uncoupling the process of cell production from drug screening. "Adding Sentigen's capabilities to our drug discovery platform gives researchers an even broader array of solutions for GPCR screening, profiling and other cellular studies," explained Nick Ecos, Vice President and General Manager of Invitrogen's Discovery Sciences business. "The synergy created by combining Invitrogen's cell and molecular biology products with Sentigen's cell-based technologies and custom services enhances our strategic commitment to scientists engaged in cell-based drug discovery by offering our clients comprehensive solutions and support," said Tom Livelli, Sentigen's President and CEO. The transaction is subject to customary closing conditions, including the approval of Sentigen's stockholders and is expected to close in the fourth quarter. Invitrogen does not expect this acquisition to have a material affect on its financials in fiscal year 2006 or decelerate the progress of its share repurchase program previously announced on August 3, 2006. "We are committed to deploying our capital for purchases of targeted acquisitions, such as Sentigen, as well as executing upon our share repurchase program," said David Hoffmeister, Invitrogen's Chief Financial Officer. "As we indicated on our earnings call, we plan to use a sizable portion of the authorization in the near term and we have already made progress towards this goal." About Invitrogen Corporation Invitrogen Corporation (Nasdaq:IVGN) provides products and services that support academic and government research institutions and pharmaceutical and biotech companies worldwide in their efforts to improve the human condition. The company provides essential life science technologies for disease research, drug discovery and commercial bioproduction. Invitrogen's own research and development efforts are focused on breakthrough innovation in all major areas of biological discovery, including functional genomics, proteomics and cell biology -- placing Invitrogen's products in nearly every major laboratory in the world. Founded in 1987, Invitrogen is headquartered in Carlsbad, Calif., and conducts business in more than 70 countries around the world. The company globally employs approximately 4,800 professionals and had revenues of more than $1.2 billion in 2005. For more information, visit www.invitrogen.com. About Sentigen Holding Corp. Sentigen Holding Corp. conducts business through two wholly-owned operating subsidiaries: Sentigen Biosciences, Inc. ("Sentigen Biosciences") and Cell & Molecular Technologies, Inc. ("CMT"). CMT provides contract research and development services to companies engaged in the drug discovery process in the following areas: molecular and cell biology, gene expression and protein biochemistry, bio-processing, high throughput screening support services, mouse genetics and cell-based GPCR selectivity profiling. Sentigen Biosciences has been primarily engaged in the development and commercialization of novel bioassay systems that elucidate the underlying biology of protein-protein interactions. Sentigen Biosciences has initially targeted its Tango(TM) Assay System to address the functionalization of G protein-coupled receptors (GPCRs) for pharmaceutical drug discovery and development. For more information on our companies, please visit their respective websites: www.cmt-inc.net and www.sentigen.com. Safe Harbor Statement Certain statements contained in this press release are considered "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, and it is Invitrogen's intent that such statements be protected by the safe harbor created thereby. Forward-looking statements include, but are not limited to: 1) Sentigen's Tango Assay System and division arrested Assay Ready Cells will improve Invitrogen's position in assay development for GPCRs; and 2) the Sentigen business will become a part of Invitrogen's Discovery Sciences Group. Potential risks and uncertainties include, but are not limited to, the risks that: a) Sentigen's technologies may not have a significant impact on Invitrogen's assay development activities; and b) Invitrogen may choose to align the business in an area outside the Discovery Sciences group., as well as other risks and uncertainties detailed from time to time in Invitrogen's Securities and Exchange Commission filings.