Maxygen, Inc. announced today the appointment of George Poste, D.V.M., Ph.D. to its Board of Directors, and several additions to its senior management team including Michael Rabson, Ph.D. as General Counsel and Senior Vice President of Legal Affairs, John Bedbrook, Ph.D., as President of Agriculture, Howard A. Simon, as Vice President of Human Resources and Administration, Stuart Pollard as Director of Protein Pharmaceutical Business Development, and Keith Powell as Vice President of Chemicals and Core Technology. Maxygen also announced the resignation of Joseph Affholter, Ph.D. as Vice President Biocatalysis and Chemicals Processing.

"Maxygen's future is dependent on the leadership of our senior management team and Board of
Directors. We have attracted a world class group of individuals to drive our future success,'' said Russell Howard, President and Chief Executive Officer. "We have strategically identified this multidisciplinary team who will provide us with tremendous breadth of experience in diverse industry areas such as pharmaceuticals, agriculture and chemicals while at the same time strengthening our business and legal expertise.''

George Poste joined Maxygen's Board of Directors in October 1999. Dr. Poste has been Chief Science and Technology Officer at SmithKline Beecham since January 1997 and is a member of the Board of Directors of SmithKline Beecham. Prior to this appointment, Dr. Poste was President of Research and Development at SmithKline Beecham. Dr. Poste is also a Research Professor at the University of Pennsylvania and holds the William Pitt Fellowship at Pembroke College, Cambridge University.

Michael Rabson, Ph.D. joined Maxygen in September 1999 as General Counsel and Senior Vice
President of Legal Affairs from Wilson Sonsini Goodrich & Rosati, P.C. where he was a member since February 1996. Dr. Rabson received his Ph.D. in infectious disease epidemiology from Yale University and did a post-doctoral fellowship at the National Cancer Institute, National Institutes of Health. He was a patent examiner at the U.S. Patent and Trademark Office before he received his J.D. from Yale Law School.

John Bedbrook, Ph.D. joined Maxygen in November 1999 as President of Agriculture from Plant
Science Ventures. Dr. Bedbrook was Chief Executive Officer of Plant Science Ventures since 1999 and Chief Technology Officer at SAVIA. Prior to joining SAVIA, Dr. Bedbrook held several senior management positions including Executive Vice President of Research and Development and Co-President at DNA Plant Technology Corp. Dr. Bedbrook received his Ph.D. in Molecular Biology from the University of Auckland in New Zealand.

Howard A. Simon joined Maxygen in November 1999 as Vice President from Landels Ripley &
Diamond, LLP where he was a partner in the Labor, Employment and Benefits group. Mr. Simon is a 1985 graduate of the Boalt Hall School of Law at the University of California, Berkeley. Also in 1985 Mr. Simon received his Master of Arts Degree with highest honors from the Graduate Theological Union of Berkeley.

Stuart Pollard, Ph.D. joined Maxygen in November 1999 as Director of Protein Pharmaceutical Business Development from Biogen. Dr. Pollard held several senior positions as Biogen including Program Executive and Business Development Manager where he ran drug discovery programs and product acquisitions. Dr. Pollard received his Ph.D. in Molecular Biology and Virology from the University of Reading in the United Kingdom.

Keith Powell, Ph.D. joined Maxygen in October 1999 as Director of Bioprocessing, and was promoted to Vice President, Chemicals and Core Technology in January 2000. Before joining Maxygen, Dr. Powell held several senior management positions at AstraZeneca including Head of Bioscience. While at AstraZeneca Dr. Powell's work focused on single cell proteins, enzymes, chemical production, high throughput screening, environmental science, biotechnology, and intellectual property. Dr. Powell was also a visiting Professor at the University of Ulster and held various positions in research and development at ICI and Glaxo. Dr. Powell received his Ph.D. in Microbial Genetics from the University of Reading in the United Kingdom.

Dr. Joseph Affholter resigned from the position of Vice President of Biocatalysis and Chemicals
Processing in January 2000 to pursue other professional and personal opportunities. While at Maxygen, Dr. Affholter helped the Company grow from approximately 30 to approximately 150 employees. As a member of Maxygen's senior management team, Dr. Affholter played a key role in developing the Company's strategic and business plans for the specific organizations he managed as well as for the Company as a whole.

Maxygen, Inc., headquartered in Redwood City, CA, is a public biotechnology company focused on creating novel products using its proprietary MolecularBreeding(TM) directed molecular evolution technologies for a broad range of industries. Maxygen's proprietary technologies bring together the advances in molecular biology and classical breeding while capitalizing on the large amount of genetic information generated by genomics. Maxygen's target markets include protein pharmaceuticals, preventative and therapeutic vaccines, chemicals and agriculture. Maxygen has strategic partnerships with several companies including Novo Nordisk in industrial enzymes, DuPont/Pioneer Hi-Bred for certain specific agricultural products, Zeneca Agrochemicals for certain specific agricultural products, DSM for improved manufacturing of certain classes of penicillin antibiotics and Rio Tinto for specific novel chemical processes. Maxygen was founded in a March 1997 spinout from GlaxoWellcome-Affymax, led by biotech entrepreneur Dr. Alejandro Zaffaroni.

Company news release
N2486