Patterns of oxygen interchange between water, substrates, and phosphate compounds of Escherichia coli and Bacillus subtilis.

摘要: Abstract The sources of oxygen in the phosphoryl moieties intracellular nucleotides and RNA under several conditions were examined with Bacillus subtilis Escherichia coli. Oxygens are representative those phosphate pool. Important findings are: 1. Under different conditions, from 50 to 80% oxygens derived medium water. A steady state level 18O acid-labile nucleoside di- triphosphates is reached within a few minutes after addition H18OH growth medium. principal routes incorporation water likely occur via exchanges oxidative phosphorylation, hydrolysis phosphates, transfer substrates partially labeled oxygens. 2. Extracellular contributes only small percentage B. even less E. This shows that turnover Pi phosphorylated substances very rapid compared net uptake 3. remaining (nearly 30 50%) must be glucose exogenously supplied metabolites. Transfer [18O]glutamate was shown amino acids reduced through ATP-linked synthetases, by dehydrogenases or phosphorylases yielding carboxyl phosphates followed transfer. Only AMP among appears serve as point entry substrate into 4. 2' - 3'-hydroxyl ribose, both, nucleosides part tabulation given enzymic reactions participating interchange