Telomerase is an enzyme that adds repetitive DNA sequences to the ends of chromosomes, called telomeres. Its primary function is to counteract the natural shortening of telomeres that occurs during cell division. Telomerase helps to maintain the length of telomeres, allowing cells to continue dividing and proliferating. In cells where telomerase activity is active, such as stem cells, germ cells, and many cancer cells, the enzyme prevents telomere erosion, thus enabling these cells to bypass the normal limit on divisions (the Hayflick limit) and maintain their replicative capacity. This function of telomerase is essential for the maintenance of tissue regeneration, but when uncontrolled, it can also contribute to the immortalization of cancer cells.
