Gene transfer between two closely related mouse cell lines has been carried out, using as the vector a cell-free preparation of metaphase chromosomes and nuclei. Distinction between gene transferents and revertants of the recipient mutant phenotype was achieved by the use of a donor strain carrying a mutationally altered (8-azaguanine-resistant) hypoxanthine-guanine phosphoribosyltransferase (H...

Ecto-5'-nucleotidase is known to be diminished markedly in activated compared to control mouse macrophages. The level of three purine nucleoside metabolizing enzymes, adenosine deaminase (EC 3.5.4.4), purine nucleoside phosphorylase (EC 2.4.2.1), and adenine phosphoribosyltransferase (EC 2.4.2.7) were measured in the sonicates of different populations of mouse peritoneal macrophages. Levels of ...

Concentration dependence of mutation in equigenerational exposures to methyl, ethyl, propyl, and butyl methanesulfonates has been determined in diploid human lymphoblasts and Salmonella typhimurium. Forward mutation was measured at the hypoxanthine guanine phosphoribosyltransferase locus in human lymphoblasts and at the putative guanine phosphoribosyltransferase locus in S. typhimurium. Reverse...

Nicotinamide phosphoribosyltransferase (NAMPT) and nicotinate phosphoribosyltransferase domain containing 1 (NAPRT1) are the main human NAD salvage enzymes. NAD regulates energy metabolism and cell signaling, and the enzymes that control NAD availability are linked to pathologies such as cancer and neurodegeneration. Here, we have screened normal and tumor samples from different tissues and pop...

IMP:pyrophosphate phosphoribosyltransferase (IPPase) (EC 2.4.2.8) has been purified over 7000-fold from human erythrocytes. The purified enzyme moved as a single band on disc electrophoresis. Antisera prepared in rabbits and rats against the purified enzyme precipitated and neutralized the enzyme, but had no effect on AMP-pyrophosphate phosphoribosyltransferase (EC 2.4.2.7) activity. Evidence w...

Enzymes involved in the metabolism of nucleic acid precursors were assayed in proliferating and maturing cells in the colon of man and in cells removed from polypoid lesions of the colon. Cells were separated from superficial and deeper layers of colonie mucosa by a recently developed tissue-planing instrument. Gradients of thymidine kinase, thymidine phosphorylase, and adenine and hypoxanthine...