PARTIAL-PURIFICATION AND IMMUNOCYTOCHARACTERIZATION OF THE PLASMA-MEMBRANE ATPASE OF JERUSALEM-ARTICHOKE (HELIANTHUS-TUBEROSUS L) TUBERS INRELATION TO DORMANCY

Plasmalemma ATPase from Jerusalem artichoke tubers was studied in rela tion to the dormancy of tubers. After partial purification, one peptid e of 110 kDa appeared on SDS PAGE electrophoresis from dormant and non -dormant materials. ATPase specific activity was twice higher on dorma nt material in the crude and solubilized fractions, but was the same i n both materials after partial purification. Immunolabeling of this en zyme was made using a specific antibody raised against the C terminal portion of the H+-ATPase from Arabidopsis thaliana. Immunolabeling was more pronounced in dormant material, in vitro and in situ. Several wo rks had shown that the C terminal part of the enzyme could be involved in its regulation. The results presented are discussed in relation to the hypothesis according to which an internal effector could modulate d the plasmalemma ATPase activity, during dormancy breaking.