Abstract: A process for inhibiting a mammalian cancerous cell or virally infected cell includes providing a Trichomonas vaginalis purine nucleoside phosphorylase enzyme or a tail mutant purine nucleoside phosphorylase enzyme in proximity to the mammalian cancerous cell or the virally infected cell and exposing the enzyme to a purine nucleoside phosphorylase enzyme cleavable substrate to yield a cytotoxic purine analog. The process includes introducing to the cell a vector containing the phosphorylase enzyme, or a DNA sequence coding for the same and delivering to the cell an effective amount of the substrate such as 9-(?-D-arabinofuranosyl)-2-fluoroadenine (F-araA).

Abstract: A host cell stably transformed or transfected by a vector including a DNA sequence encoding for mutant purine nucleoside cleavage enzymes is provided. The transformed or transfected host cell can be used in combination with a purine substrate to treat tumor cells and/or virally infected cells. A nucleotide sequence encoding mutant E. coli derived purine nucleoside phosphorylase proteins which can be used in conjunction with an appropriate substrate to produce toxins which impair abnormal cell growth is also provided. A method is detailed for the delivery of toxin by generation within target cells or by administration and delivery to the cells from without. Novel purine nucleosides are detailed that yield a cytotoxic purine upon enzymatic cleavage. A synthetic process for nucleosides is also detailed.

Abstract: The present invention provides a procaryotic host cell stably transformed or transfected by a vector including a DNA sequence encoding for mutant purine nucleoside phosphorylase or hydrolase. The transformed or transfected procaryotic host cell can be used in combination with a purine substrate to treat tumor cells and/or virally infected cells. The present invention provides nucleotide sequences encoding mutant E. coli derived purine nucleoside phosphorylase proteins which can be used in conjunction with an appropriate substrate to produce toxins which impair abnormal cell growth. The invention provides for delivery of the toxin by generation within target cells or by administration and delivery to the cells from without.

Abstract: The present invention provides a procaryotic host cell stably transformed or transfected by a vector including a DNA sequence encoding for mutant purine nucleoside phosphorylase or hydrolase. The transformed or transfected procaryotic host cell can be used in combination with a purine substrate to treat tumor cells and/or virally infected cells. The present invention provides nucleotide sequences encoding mutant E. coli derived purine nucleoside phosphorylase proteins which can be used in conjunction with an appropriate substrate to produce toxins which impair abnormal cell growth. The invention provides for delivery of the toxin by generation within target cells or by administration and delivery to the cells from without.