Telomerase from Saccharomyces cerevisiaecontains several protein subunits and may have different activities depending on the protein content

Telomerase is a ribonucleoprotein responsible for maintaining telomeres during the cell cycle [1, 2]. Here we describe a two‐step purification procedure for the Saccharomyces cerevisiaetelomerase complex. We have found that the properties (processivity, nuclease activity) of telomerase depend on the isolation procedure. Using a cross‐linking approach, we have revealed several proteins that could be components of the telomerase complex. Furthermore, spectra of cross‐linked proteins differ in processive and non‐processive telomerase complexes.