Glucan-phosphorylase forms in cotyledons of Pisum sativum L.: Localization,developmental change,in-vitro translation,and processing |
| |
Authors: | Joachim van Berkel Jutta Conrads-Strauch Martin Steup |
| |
Institution: | (1) Institut für Botanik, Westfälische Wilhelms-Universität Münster, Schlossgarten 3, W-4400 Münster, Germany;(2) Present address: Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, 30 Köln, Germany;(3) Present address: John Innes Institute, Colney Lane, NR4 7UH Norwich, UK |
| |
Abstract: | The occurrence, location, and biosynthesis of glucan-phosphorylase (EC 2.4.1.1) isoenzymes were studied in cotyledons of developing or germinating seeds of Pisum sativum L. Type-I and type-II isoenzymes were detected, and were also localized by indirect immunofluorescence using polyclonal anti-type-I or anti-type-II phosphorylase antibodies. Type-I isoenzyme was found in the cytosol of parenchyma cells whereas the type-II enzyme form is a plastid protein which resides either in amyloplasts (in developing seeds) or in proplastids (in germinating seeds). During seed development, type-II phosphorylase was the predominant isoenzyme and the type-I isoenzyme represented a very minor compound. During germination, the latter increased whilst type-II phosphorylase remained at a constant level. In in-vitro translation experiments, type-I isoenzyme was observed as a final-size product with an apparent molecular weight of approx. 90 kDa. In contrast, type-II phosphorylase was translated as a high-molecular-weight precursor (116 kDa) which, when incubated with a stromal fraction of isolated intact pea chloroplasts, was processed to the size of the mature protein (105 kDa).Abbreviations IgG
immunoglobulin G
- kDa
kilodalton
- poly(A)+ RNA
polyadenylated RNA
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
This work has been made possible by grants from the Deutsche Forschungsgemeinschaft. The authors are endebted to Mrs. Karin Niehüser for help in the immunocytochemical studies. |
| |
Keywords: | Glucan phosphorylase Isoenzyme processing Pisum Starch metabolism |
本文献已被 SpringerLink 等数据库收录! |
|