Synthesis of Canavalin and Concanavalin A in Maturing Canavalia gladiata Seeds

In successive stages of seed development of Canavalia gladiata, seeds were harvested, and time-course changes of the accumulation of canavalin and concanavalin A (Con A) were investigated by SDS-gel electrophoresis and protein blot analysis. Results showed that the synthesis of both seed proteins started as early as 30 days after flowering (DAF) and that they had different accumulation patterns during seed development. The synthesis and accumulation of canavalin were most active at SOSO DAF, whereas the content of Con A continued to increase gradually until the seed maturation was nearly completed (80 DAF). Next, an RNA fraction was prepared from seeds of 40 DAF, translated in a wheat germ system and its translation products analyzed by the immunoprecipitation and SDS-gel electrophoresis. The mol wt (about 48,000) of the in vitro product immunoprecipitated with the antiserum to canavalin was very closed to that of canavalin. The mol wt (34,000) of the in vitro product immunoprecipitated with the antiserum to Con A was about 4,000 higher than that of Con A. Canavalin-mRNA was present as early as at 30 DAF and its translational activity was the highest at 35–40 DAF. Con A-mRNA was also detected at 30 DAF and, in contrast to canavalin-mRNA, high activities were maintained until 75 DAF.