Mono‐ADP‐Ribosylation of Arginine Residue of Euglena gracilis Z in Synchronous Culture

ABSTRACT. In Euglena gracilis Z, a considerably high activity of mono‐ADP‐ribosyltransferase occurred and change of it was accompanied by a cell cycle induced by a light‐dark cycle. The enzyme activity was strongly inhibited by L‐arginine and supported in the presence of poly‐L‐arginine as a substrate, indicating that ADP‐ribosylated amino acid is an arginine residue. Arginine: mono‐ADP‐ribosyltransferase activity was found in the chloroplasts, mitochondria, microsomes and cytosol as judged from marker enzyme activities and the activity in each organelle fluctuated with the cell cycle.