SAN DIEGO -- A South Dakota businessman pledged $50 million to the Burnham Medical Research Institute in La Jolla, which will be renamed for the donor, it was announced Tuesday.

The gift from Denny Sanford, who gave $20 million to the institute to create the Sanford Children's Health Research Center at Burnham in 2007, will result in the renaming of the larger institute as the Sanford-Burnham Medical Research Institute.

"Since the Sanford Children's Health Research Center was established, I have had the opportunity to observe the incredible research being conducted by Burnham scientists," Sanford said. "With this gift I have challenged others to join me in supporting this life-changing science."

Sanford's latest gift will be made available in $10 million donations over five years.

The La Jolla institute is not the only life science organization in San Diego to receive a gift from Sanford, who made much of his fortune in the banking industry.

In 2008, Sanford donated $30 million to the San Diego Consortium for Regenerative Medicine, now known as the Sanford Consortium for Regenerative Medicine, to construct its state-of-the-art stem cell research facility. Burnham is a member of the Consortium.

The governor applauded the gift.

"California is home to the world's finest biotechnology businesses and institutions that are not only producing a healthier tomorrow but also providing hundreds of thousands of jobs and generating tens of billions of dollars in economic impact in our state today," Gov. Arnold Schwarzenegger said.

Sanford, who is worth about $1 billion, ranks No. 701 on Forbes' list of the richest people in the world.