Gainesville’s Chattahoochee Bank of Georgia has been purchased by North Carolina-based Entegra Financial Corp., the holding company of Entegra Bank. The purchase of Chattahoochee with a mix of stock and cash was announced on Tuesday. Entegra paid $34.9 million — 70 percent cash and 30 percent stock — for the commercial bank on E.E. Butler Parkway, according to the announcement.