Sharing information across different organizations is a critical problem. Using security enforcement mechanisms, accessing databases is limited to authorized users only. However, if databases and access control policies are syntactically and schematically heterogeneous, information interoperation becomes a crucial challenge. In order to allow users from multiple organizations to access databases, a better access control model is desired. In this paper, we propose Semantic Access Control based on popular Role-Base Access Control. Semantic Access Control provides secure access control to databases while resolving the heterogeneity among the databases. We present Semantic Access Control Enabler (SAGE), a novel middleware-based system that has been designed and implemented to enable Semantic Access Control on the Web. SAGE is a middleware system that requires only a few changes to be done on the legacy systems of any organizations involved. Unlike traditional mediator technologies, we integrate heterogeneity resolution and access control into one process, We show that despite performing ontology mappings and query and data translations our toolkit still provides acceptable performance.