Synthesis of a Vacuolar Acid Invertase in Washed Discs of Storage Root Tissue 11Beta vulgaris L)

The synthesis of acid invertase during washing of red beet storageroots has been investigated using protein synthesis inhibitors,antibiotics, and antibodies raised against the purified invertase.Acid invertase increased during the first 3 d of washing thendecreased, with the rates of both processes dependent on temperature.Concomitantly, acid phosphatase declined throughout this period.Activity gels confirmed the increase in the level of activeinvertase protein. The increase in activity was prevented bycycloheximide, monensin, tunicamycin, and carbonyl cyanide m-chlorophenylhydrazone.Leakage of betanin was measured and ultrastructural observationsundertaken to ensure these compounds had no non-specific effects.Immunoblotting confirmed the synthesis of a new 65 kDa invertaseduring washing and its subsequent loss. The location of theinvertase was investigated by immunoblotting of proteins invacuoles isolated from fresh and washed storage root discs,and indicated that the invertase is localized in the vacuole.The results are discussed in relation to the synthesis and targetingof invertase during the changes induced by washing. Key words: Acid invertase, Beta vulgaris L., protein synthesis, protein targeting, vacuole