The K m and V max values for a set of primers: d(pT)n (pC)(pT)m (n=3–9.m=0–7) and d(pT)4 (pCpG)4 (pT)4 (k=1–5) have been estimated. Poly(dA) was used as template. The number of complementary bases from the 3′ end to a noncomplementatry ones was shown to determine the efficiency of interaction of d(pT)n (pC) (pT)m with the Klenow fragment. Oligonucleotides d(pT)4 (pCpG)4 (pT)4 in solution forming duplexes containing hairpin-like elements, show a higher affinity to the enzyme that control d(pT)4, d(pT)n, and d(pT)n (pC)(pT)m primers. For example, the K m value (1.1 nM) for d(pT)4 (pCpG)5 (pT)4 is about 14,000 and 200 times lower than those for d(pT)4 and d(pT)? respectively. Possible reasons for such an abnormally high affinity of the above primers are discussed.
