5'-NUCLEOTIDASE .2. SIGNIFICANCE OF 5'-NUCLEOTIDASE IN METABOLISM OF NUCLEOTIDES STUDIED BY HISTOCHEMICAL AND BIOCHEMICAL METHODS

To get more insight in the function of 5′-nucleotidase catabolic and anabholic processes were investigated in which 5-nucleotides are involved. The catabolism of adenosine-5-monophosphate was studied by investigating the reaction products obtained after incubation of homogenates of several organs of rat and mouse with adenosine-5-monophosphate and with adenosine. Two experimental tumours of the mouse were investigated in the same way. It was found that in tissues containing a high activity of 5′-nucleotidase other enzymes involved in the catabolism of 5-nucleotides, such as nucleosidase, adenosine deaminase and adenosine-5-monophosphate deaminase could also be demonstrated. The anabolic processes in which 5-nucleotides are involved had been studied by investigating the incorporation of tritium-labeled thymidine in several tissues of the mouse. It appeared that in cells showing a high 5′-nucleotidase activity no incorporation of radioactive thymidine could be found, while in cells showing incorporation of thymidine enzyme activity could not be demonstrated. A discussion is given about the possible role of 5′-nucleotidase in the control of nucleic acid biosynthesis and in the catabolism of nucleic acids. © 1968 Springer-Verlag.