Inorganic phosphatases and phosphagen kinase in Euglena gracilis

1. 1. Metaphosphatase, pyrophosphatase and ATP: arginine phosphokinase were studied in extract of bleached Euglena gracilis. 2. 2. Metaphosphatase presents two optimal values, one bctwecn pH 6-6.5 and the other at pH 7.5; pyrophosphatase has an optimum at pH 7.5. 3. 3. ATP: arginine phosphokinase, investigated in the reverse reaction is markedly activated by Ca2+ ions, and the pH optimum is 9. 4. 4. The presence of ATP: arginine phosphokinase activity in Euglena gracilis suggests that this phytoflagellate utilizes phosphoarginine or a phosphoarginine-like compound as energy donor while polyphosphates function as storage of inorganic phosphorus. © 1977.