Аннотация:Telomerase is a specialized reverse transcriptase responsible for maintaining the termini of linear chromosomes. The human enzyme is a ribonucleoprotein complex minimally comprising a catalytic protein moiety (hTERT) and an RNA subunit (hTR) which acts as the template for the reverse transcriptase reaction. Inhibiting or blocking the activity of telomerase may be an important approach to targeting cancer, that may be applicable in a tumor types with short telomere. Nowadays, there was developed telomerase inhibitor – Imetel- stat(GRN163L) which has complementary sequence to hTR and which in clinical trial. Our goal was measuring the kinetic param- eters of inhibition of telomerase by telomerase template antago- nist analog of GRN163. In contrast to GRN163 which has tio- phosphoroamidate modification in backbone, we used meG- RN163 which has same sequence but has 2′OMe modification. We found that oligonucleotides with telomere sequences inhibit the PCR of RQ-TRAP. Though, we improved RQ-TRAP by adding dilution step before PCR. But that step greatly reduces the signal. To overcome that problem, we improved system by the over-expression of telomerase components (by enhancing 3-fold). Additionally we used the precipitation of telomerase from cell extract for fast purification and concentration of telomerase. This purification was enough to provide stability of oligonucleo- tides in telomerase rich cell extract. The kinetic parameters of inhibition of telomerase by telomerase template antagonists were determined. Also we used our new improved methods on deter- mining the kinetic parameters of RNA-quadruplex.