An investor group lead by Prospect Medical Holdings Inc., a health care management company, has entered into an agreement to purchase the 420-bed Brotman Medical Center in Culver City, Tenet Healthcare Corp. announced Friday.

Culver City-based Prospect has agreed to continue operating the medical center as an acute care hospital, and retain its emergency room. The sale is expected to be completed by July 31 and net Tenet $27 million in after-tax proceeds.

The sale leaves Tenet with only five more hospitals on the auction block. Last year, Tenet announced plans to sell 27 hospitals nationwide as part of a restructuring plan prompted by its regulatory troubles over its Medicare billing practices. Among the local hospitals still for sale is Encino-Tarzana Regional Medical Center.

Prospect provides management services to independent physician associations. Its chairman and chief executive is Dr. Jacob Terner, a former member of Brotman’s medical staff. Terner also served as chairman and chief executive of Century MediCorp Inc. from 1988 to 1992 prior to its merger with a predecessor of Health Net Inc. Century operated a health maintenance organization but also owned two hospitals.