M. Cercos et J. Carbonell, PURIFICATION AND CHARACTERIZATION OF A THIOL-PROTEASE INDUCED DURING SENESCENCE OF UNPOLLINATED OVARIES OF PISUM-SATIVUM, Physiologia Plantarum, 88(2), 1993, pp. 267-274
A senescence-specific protease has been purified from senescent unpoll
inated ovaries of Pisum sativum L. cv. Alaska by acidic extraction, (N
H4)2SO4 fractionation, ion exchange chromatography on CM-Sephadex, and
affinity chromatography on ribulose-1,5-bisphosphate carboxylase/oxyg
enase (Rubisco)-Sepharose. Characterization of the purified protease i
ndicated that it is a thiol-endoprotease (EC 3.4.22 class) active over
a wide pH range. Purified antibodies against this protease inhibit th
e degradation of Rubisco in autodigested extracts of senescent ovaries
, suggesting that Rubisco might be a substrate for the protease in sen
escent pea ovaries. The relative levels of the protease were determine
d by an enzyme-linked immunosorbent assay (ELISA) along the processes
of ovary senescence and gibberellic acid (GA)-induced fruit developmen
t, indicating its induction at the beginning of senescence and the sup
pression of its synthesis by GA treatment.