A cofactor requirement for polygalacturonase from Cuscuta campestris

The occurrence of a polygalacturonase in tissue of Cuscuta is reported. The enzyme activity requires the presence of a cofactor, which can be removed by dialysis. The cofactor is hear stable and extractable in 80% methanol or in petroleum ether. It appears to be a low molecular weight peptide, since its activity is lost on incubation with proteinase K or papain. The exact nature and the possible function of this co-factor in the breakdown of pect ins by Cuscuta are under investigation. (C) 1999 Elsevier Science Ltd. All rights reserved.