- Substrate/inhibitor specificities of human deoxycytidine kinase (dCK) and thymidine kinases (TK1 and TK2). Kierdaszuk, B., Krawiec, K., Kazimierczuk, Z., Jacobsson, U., Johansson, N.G., Munch-Petersen, B., Eriksson, S., Shugar, D. Adv. Exp. Med. Biol. (1998)