Transient occurrence of lipoxygenase and glycoprotein gp49 in lipid bodies during fat mobilization in anise seedlings

Abstract

The patterns of lipid-body proteins prepared at different stages of germination from seedlings of anise (Pimpinella ansium L.) were investigated. During the stage of fat mobilization, a set of proteins is synthesized de novo and transferred to existing lipid bodies. Analysis of the protein constituents, detected either by protein staining, concanavalin-A/peroxidase staining or immunoreaction on Western blots showed three distinct protein species: a lipoxygenase firmly integrated into the lipid bodies, a glycoprotein gp50 only extractable from the lipid bodies by treatment with sodium dodecyl sulfate and a glycoprotein gp49 solubilized by diethyl-ether treatment of lipid bodies. Both the lipoxygenase immunodetected on Western blots and gp49 stained with concanavalin-A/ peroxidase conjugate occurred transiently in the lipidbody fraction, reaching maximum concentrations between days 6 and 13 of germination. This behavior was in contrast to the decreasing level of the 18.4-kDa oleosin already present at the beginning of germination.