Abstract: The invention relates to a multifunctional nucleoside didesoxyribosyl or nucleoside deoxyribosyl transferase which has one or more of the following additional activities (desoxy) nucleoside kinase, nucleoside reductase desaminase, or DNA polymerase activity. Utilizing the multifunctional enzyme results in a variety of nucleic acid products. These products can be prepared using sequential reactions in a single batch process wherein the sequential reaction can be caused to occur by varying process conditions in a manner which turns on or off the requisite activities causing the sequential reactions to occur. An example of a product prepared in this manner is dideoxyribofuranoside triphosphate. Certain of the resultant products have pharmaceutical activities, e.g. antiviral agents. Lactobacillus leichmannii (DSM 20076) is a source of the multifunctional nucleoside deoxyribosyl transferase.