David R. King, a lawyer-turned-chief executive officer who ran and sold three Philadelphia-area biotech firms, is moving to the other side of the transaction ledger.

King is joining $700-million-asset investment firm Quaker BioVentures Inc., of West Philadelphia, as a venture partner focusing on merger-and-acquisition deals.

Quaker partner Sherrill Neff said the biotech sector was primed for a big expansion in the Philadelphia region, as the traditional pharmaceutical companies, which rank among the region's largest employers, buy small biotech firms in hopes of adding profitable products.

The fund, which invests in small companies from New England to the Carolinas, is backed by more than $160 million committed by Pennsylvania's state pension funds, plus additional financing from the state's tobacco-settlement money.

King, a Penn and Harvard Law graduate, built a biotech and emerging-company law practice during a 26-year career at Morgan, Lewis & Bockius L.L.P.

He was a director and confidant of CEO Frank Baldino at Cephalon Inc., said Mickey Flynn, former head of Puresyn Inc., of Malvern, and president of the Pennsylvania Biotechnology Association. "He was instrumental in helping Frank Baldino in the development of Cephalon in the early days," Flynn said.

"He's Mr. Biotech," said Stephen Goodman, senior partner in charge of the group King developed at Morgan Lewis. "He built a dominant life-sciences practice in Philadelphia."

King said he quit Morgan Lewis in 2000 after reflecting that he "was working harder than ever." He joined Principia Pharmaceutical Corp. in King of Prussia, as CEO, and sold it at a big profit to Human Genome Sciences Inc.

"And I never looked back," King said.

He repeated the trick as president of Delsys Pharmaceutical Corp., of Princeton, selling it to Elon Corp., and as CEO of BioRexis, which Quaker helped fund, before it was purchased last year by Pfizer Inc.

Neff said Quaker typically reviewed more than 600 business plans a year and invested "in four to six."

"People approach me with business plans in the supermarket, at weddings, at bar mitzvahs," King said. "It's great."

Contact staff writer Joseph N. DiStefano at 215-854-5194 or jdistefano@phillynews.com.