Isolation and partial characterization of DNA polymerases from Crithidia fasciculata.

Two types of DNA polymerase activity were partially purified from Crithidia fasciculata. The alpha-type, DNA polymerase A, was of high molecular weight and sensitive to N-ethylmaleimide, whereas the beta-type, DNA polymerase B, was of low molecular weight and resistant to N-ethylmaleimide. Phosphocellulose chromatography revealed multiple peaks of DNA polymerase A activity the properties of which, such as pH optimum, salt sensitivity, utilization of synthetic template-initiator complexes and response to DNA polymerase inhibitors were similar. The response of the C. fasciculata DNA polymerase A enzymes to some of these inhibitors and utilization of poly(rA) X oligo(dT)11 showed these enzymes to be markedly different from mammalian DNA polymerase alpha.