Organelle formation in the presence of a protease inhibitor

Abstract

Light-dependent chlorophyll formation and growth of Euglena is blocked by the protease inhibitor phenylmethane sulfonyl fluoride (PMSF). Inhibition of chlorophyll formation can be completely relieved by addition of ammonium phosphate, and to a limited extent by some amino acids. Growth is not resumed upon addition of nitrogen sources. PMSF inhibits protease activity from Euglena extracts. It is proposed that light stimulates a protease dependent break-down of protein to supply nitrogen for organelle biosyntheses.