Abstract
CND41, a 41kDa DNA-binding protease isolated from tobacco chloroplast nucleoids, has been shown to degrade denatured Ruisco in vitro at physiological pH. The involvement of CND41 in vivo degradation of Rubisco in senescent leaves was also confirmed in transgenic tobacco with reduced CND41. In this report, we investigated the regulation of CND41 protease activity during the senescence. For this purpose, we prepared specific antibodies against CND41-specific peptide and analyzed the accumulation of CND41 during the senescence in whole plants. Immuno-blot analyses clearly showed the increased accumulation of CND41 during senescence and the processing to slightly shorter fragment. Additional analyses in CND41 overproducing tobacco suggested that the processing of CND41 was important for the activation of protease activity. Purification of processed CND41 and its biochemical characterization is on going.
