1. Cell wall-bound cationic and anionic class III isoperoxidases of pea root: biochemical characterization and function in root growth.
- Author
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Kukavica BM, Veljovicc-Jovanovicc SD, Menckhoff L, and Lüthje S
- Subjects
- Anions metabolism, Cations metabolism, Chelating Agents pharmacology, Chitosan pharmacology, Concanavalin A pharmacology, Electrophoresis, Polyacrylamide Gel, Enzyme Inhibitors pharmacology, Glycosylation, Indoleacetic Acids pharmacology, Isoelectric Focusing, Isoenzymes antagonists & inhibitors, Isoenzymes chemistry, Isoenzymes isolation & purification, Isoenzymes metabolism, Kinetics, Lectins pharmacology, Molecular Weight, Oxidation-Reduction, Pisum sativum drug effects, Pisum sativum growth & development, Peroxidase antagonists & inhibitors, Peroxidase chemistry, Peroxidase isolation & purification, Plant Growth Regulators pharmacology, Plant Proteins antagonists & inhibitors, Plant Proteins chemistry, Plant Proteins isolation & purification, Plant Proteins metabolism, Plant Roots drug effects, Plant Roots growth & development, Cell Wall enzymology, Pisum sativum enzymology, Peroxidase metabolism, Plant Roots enzymology
- Abstract
Cell wall isolated from pea roots was used to separate and characterize two fractions possessing class III peroxidase activity: (i) ionically bound proteins and (ii) covalently bound proteins. Modified SDS-PAGE separated peroxidase isoforms by their apparent molecular weights: four bands of 56, 46, 44, and 41kDa were found in the ionically bound fraction (iPOD) and one band (70kDa) was resolved after treatment of the cell wall with cellulase and pectinase (cPOD). Isoelectric focusing (IEF) patterns for iPODs and cPODs were significantly different: five iPODs with highly cationic pI (9.5-9.2) were detected, whereas the nine cPODs were anionic with pI values between pH 3.7 and 5. iPODs and cPODs showed rather specific substrate affinity and different sensitivity to inhibitors, heat, and deglycosylation treatments. Peroxidase and oxidase activities and their IEF patterns for both fractions were determined in different zones along the root and in roots of different ages. New iPODs with pI 9.34 and 9.5 were induced with root growth, while the activity of cPODs was more related to the formation of the cell wall in non-elongating tissue. Treatment with auxin that inhibits root growth led to suppression of iPOD and induction of cPOD. A similar effect was obtained with the widely used elicitor, chitosan, which also induced cPODs with pI 5.3 and 5.7, which may be specifically related to pathogen defence. The differences reported here between biochemical properties of cPOD and iPOD and their differential induction during development and under specific treatments implicate that they are involved in specific and different physiological processes.
- Published
- 2012
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