Maxygen, Inc. today announced that it has obtained an exclusive worldwide license from the
California Institute of Technology (Caltech) for the Staggered Extension Process (StEP) directed evolution technology developed in the laboratory of Dr. Frances Arnold. Maxygen has also entered into a research collaboration agreement with Dr. Arnold for the advancement of directed evolution
technologies.

"The Caltech StEP technology is a useful addition to Maxygen's growing patent portfolio of recombination technologies" said Russell Howard, Ph.D., Maxygen's President and CEO. "We are very pleased to be working with Dr. Arnold and her lab to advance directed evolution technologies towards generation of important commercial products."

"I am delighted to be working with Maxygen to create new opportunities for biotechnology through directed evolution," said Dr. Arnold. "These technologies have opened up a whole new future for biotechnology in medicine, in environmental protection and in many other important industries. Maxygen is the leader in this area, with a phenomenal combination of vision and technology. I'm proud to be involved."

Maxygen, Inc. is a private biotechnology company headquartered in Redwood City, CA that is focused on the development of directed evolution technologies known as DNA Shuffling or Molecular Breeding to provide value to a broad range of applications including human therapeutics, chemicals, vaccines, gene therapy, industrial enzymes, agriculture and nutraceuticals. The Company is the leader in nucleic acid recombination technologies for evolving new properties into single genes, multi-gene systems, pathways, vectors and genomes. Maxygen has commercial relationships with several companies including Novo Nordisk in certain areas of industrial enzymes, DuPont/Pioneer Hi-Bred for specific products in agriculture, and DSM Anti-Infectives/Gist Brocades for improved manufacturing of certain classes of penicillin antibiotics. Maxygen was founded in a March 1997 spinout from Glaxo Wellcome-Affymax, led by biotech entrepreneur Alejandro Zaffaroni, and DNA Shuffling inventor Pim Stemmer.

Company news release
N1782