Characterisation of two protein phosphatase 2A holoenzymes from maize seedlings
| Autor: | Olubunmi S. Awotunde, Grażyna Muszyńska, S. Zolnierowicz, E. Sugajska |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
chemistry.chemical_classification
Protein subunit Biophysics Peptide Protein phosphatase 2 Okadaic acid Biology Biochemistry Molecular biology Zea mays Chromatography DEAE-Cellulose chemistry.chemical_compound chemistry Holoenzymes Histone H1 Structural Biology Plant protein Phosphoprotein Phosphatases Electrophoresis Polyacrylamide Gel Amino Acid Sequence Protein Phosphatase 2 Molecular Biology Peptide sequence |
| Zdroj: | Biochimica et biophysica acta. 1480(1-2) |
| ISSN: | 0006-3002 |
| Popis: | Two holoenzymes of protein phosphatase 2A (PP2A), designated PP2AI and PP2AII, were purified from maize seedlings. The subunit composition of maize holoenzymes generally resembled those of animal PP2A. Using SDS/PAGE and Western blots with antibodies generated against peptides derived from animal PP2A, we established the subunit composition of plant protein phosphatase 2A. In both maize holoenzymes, a 38000 catalytic (PP2Ac) and a 66000 constant regulatory subunit (A) constituting the core dimer of PP2A were present. In addition, PP2AI (180000-200000) contained a protein of 57000 which reacted with antibodies generated against the peptide (EFDYLKSLEIEE) conserved in all eukaryotic Balpha regulatory subunits. In contrast, none of the proteins visualised in PP2AII (140000-160000) by double staining reacted with these antibodies. The activity of PP2AI measured with (32)P-labelled phosphorylase a in the presence of protamine and ammonium sulfate is about two times higher than that of PP2AII. PP2AI and PP2AII displayed different patterns of activation by protamine, polylysine and histone H1 and exhibit high sensitivity toward inhibition by okadaic acid. The data obtained provide direct biochemical evidence for the existence in plants of PP2A holoenzymes composed of a catalytic subunit complexed with one or two regulatory subunits. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|