A pectin Lyase Inhibitor Protein from Cell Walls of Sugar Beet

Abstract

A protein from sugar beet roots inhibited pectin lyase (PNL) that was isolated from Rhizoctonia solani. The PNL inhibitor protein (PNLIP) was extracted from healthy sugar beet cell walls and partially purified by ammonium sulfate fractionation, cation exchange, and gel permeation chromatography. Electrophoresis in polyacrylamide with sodium dodecyl sulfate showed a single major band of 57.5 kDa. Isoelectric focusing gave a major band at pI 9.9. Kinetic analysis indicated that the inhibition was uncompetitive (coupling). Pectin lyase inhibitory activity was greater in cell wall extracts from rotted and adjacent tissue than in healthy tissue []