Inhibitors of polygalacturonase in calli of Orobanche aegyptiaca.

The presence of at least three distinct polygalacturonases (PGase) in callus of Orobanche was demonstrated. The PGase activity is labile and at pH 4.5 does not require activation by cations. It can be partially purified on Biogel P 100 columns and can be resolved by PAGE into several bands. Broomrape callus tissue also contains inhibitors of PGase activity. One of these is a low M(r) compound, stable to boiling and removable by dialysis. An additional inhibitor precipitable by ammonium sulphate is also present.