Alkaline phosphatase of <Emphasis Type="Italic">Physarum polycephalum</Emphasis> is insoluble |
| |
Authors: | Kiyoshi Furuhashi |
| |
Institution: | (1) Faculty of Education, Shiga University, Hiratsu 2-5-1, Otsu Shiga, 520-0862, Japan |
| |
Abstract: | The plasmodia of Physarum polycephalum grow as multinucleated cells in the presence of sufficient humidity and nutriment. Under non-illuminating conditions, stresses
such as low temperature or high concentrations of salts transform the plasmodia into spherules whereas dehydration induces
sclerotization. Some phosphatases including protein phosphatase and acid phosphatase have been purified from the plasmodia,
but alkaline phosphatase remains to be elucidated. Phosphatase of the plasmodia, spherules and sclerotia was visualized by
electrophoresis gel-staining assay using 5-bromo-4-chloro-3-indolyl phosphate. Insoluble fractions of the sclerotia were abundant
in phosphatase activity. The phosphatase which was extracted by nonionic detergent was subjected to column chromatography
and preparative electrophoresis. Purified phosphatase showed the highest activity at pH 8.8, indicating that this enzyme belongs
to alkaline phosphatase. The apparent molecular mass from sodium dodecyl sulfate-polyacrylamide gel electrophoresis under
non-reducing condition was estimated to be 100 kDa whereas that under reducing was 105 kDa. An amount of 1% sodium dodecyl
sulfate or 0.5 M NaCl had no effects on the activity although the phosphatase showed heat instability, Mg2+-dependency and sensitivity to 2-glycerophosphate or NaF. The extracting conditions and enzymatic properties suggest that
this alkaline phosphatase which is in a membrane-bound form plays important roles in phosphate metabolism. |
| |
Keywords: | Physarum polycephalum Myxomycetes Slime mold Plasmodia Spherules Sclerotia Phosphatase |
本文献已被 PubMed SpringerLink 等数据库收录! |
|