The binding of 4-dimethylaminoazobenzene to proteins and the enzymatic activities of some purine-catabolyzing enzymes during feeding of the carcinogen have been in vestigated by analysis of two liver fractions differing in their cytological composition. At an early stage of feeding dye binding occurred at a faster rate in nonparenchymal cells than in parenchymal cells. Binding in nonparenchymal...

Amide and ureide biogenic enzymes were measured in the plant fraction of soybean (Glycine max) nodules during the period 11 to 23 days after inoculation with Rhizobium japonicum (USDA 3I1b142). Enzymes involved in the initial assimilation of ammonia, i.e. glutamine synthetase, glutamate synthase, and aspartate aminotransferase, showed substantial increases in their specific activities over the ...

Pseudomonas fluorescens Pf0-1 is one of the model organisms for biofilm research. Our previous transposon mutagenesis study suggested a requirement for the de novo purine nucleotide biosynthesis pathway for biofilm formation by this organism. This study was performed to verify that observation and investigate the basis for the defects in biofilm formation shown by purine biosynthesis mutants. C...

Brine shrimp are incapable of synthesizing purines de nova and seemingly have a complex nucleotide metabolism involving conversion of stored diguanosine 5’, 5/“-(PI, P4tetraphosphate) into ATP. When nucleosides uniformly labeled with 14C are administered to the organism, its ATP shows an unusual labeling pattern. When [UJ4C]adenosine is used as a precursor, the purine moiety is primarily incorp...

The de novo biosynthesis of purines is carried out by a highly conserved metabolic pathway that includes several validated targets for anticancer, immunosuppressant, and anti-inflammatory chemotherapeutics. The six enzymes in humans that catalyze the 10 chemical steps from phosphoribosylpyrophosphate to inosine monophosphate were recently shown to associate into a dynamic multiprotein complex c...

The ZTP riboswitch is a widespread family of regulatory RNAs that upregulate de novo purine synthesis in response to increased intracellular levels of ZTP or ZMP. As an important intermediate in purine biosynthesis, ZMP also serves as a proxy for the concentration of N10-formyl-tetrahydrofolate, a key component of one-carbon metabolism. Here, we report the structure of the ZTP riboswitch bound ...

Increasing incidences of human disease, crop destruction and ecosystem perturbations are attributable to fungi and threaten socioeconomic progress and food security on a global scale. The blast fungus Magnaporthe oryzae is the most devastating pathogen of cultivated rice, but its metabolic requirements in the host are unclear. Here we report that a purine-requiring mutant of M. oryzae could dev...

Prevention of nucleoside loss in bile is physiologically desirable because hepatocytes are the main source of nucleosides for animal cells which lack de novo nucleoside biosynthesis. We have demonstrated a Na+ gradient-energized, concentrative nucleoside transport system in canalicular membrane vesicles (CMV) from rat liver by studying [3H]adenosine uptake using a rapid filtration technique. Th...