US Patent 8936911 Purified extended polymerase/template complex for sequencing

Methods, Compositions, and Systems are provided for obtaining polymerase-template complex mixtures with improved levels of active polymerase. In some aspects, methods are described in which a polymerase-template complex is exposed to reaction conditions in which a complementary strand to the template is produced. The extended reaction mixture is purified, for example by gel filtration chromatography to produce a mixture of polymerase-template complex having a higher active fraction. This purified mixture can be used for further analyses including single molecule sequencing.