TY - JOUR
T1 - Demonstration of separate phosphotyrosyl- and phosphoseryl-histone phosphatase activities in the plasma membranes of a human astrocytoma
AU - Leis, Jose F.
AU - Knowles, Aileen F.
AU - Kaplan, Nathan O.
N1 - Funding Information:
We thank the staff of the Athymic Mouse Facility at UCSD (supported by NC1 Grant CA-23052) for providing the human astrocytoma xenografts.
Funding Information:
i This paper is dedicated to Dr. B. L. Horecker the occasion of his 70th birthday. 2This work was supported by Grant CA-11683 from the National Cancer Institute, and PHS Grant T35 HL07479.
PY - 1985/6
Y1 - 1985/6
N2 - A plasma membrane preparation from a human astrocytoma contained p-nitrophenyl phosphate (pNPP), phosphotyrosyl histone, and phosphoseryl histone hydrolysis activities. The pNPPase and phosphotyrosyl histone phosphatase activities were inhibited by vanadate, whereas the phosphoseryl histone phosphatase activity was not; the latter activity was inhibited by pyrophosphate and nucleoside di- and triphosphates. When the membranes were solubilized by Triton X-100 and the solubilized proteins were subjected to column chromatography on DEAE-Sephadex, Sepharose 6B-C1, and wheat germ agglutinin-Sepharose 4B columns, the pNPPase activity coeluted with the phosphotyrosyl histone phosphatase activity, and was separable from the phosphoseryl histone phosphatase activity. The results from column chromatography also indicated that there may be multiple phosphotyrosyl and phosphoseryl protein phosphatases in the plasma membranes.
AB - A plasma membrane preparation from a human astrocytoma contained p-nitrophenyl phosphate (pNPP), phosphotyrosyl histone, and phosphoseryl histone hydrolysis activities. The pNPPase and phosphotyrosyl histone phosphatase activities were inhibited by vanadate, whereas the phosphoseryl histone phosphatase activity was not; the latter activity was inhibited by pyrophosphate and nucleoside di- and triphosphates. When the membranes were solubilized by Triton X-100 and the solubilized proteins were subjected to column chromatography on DEAE-Sephadex, Sepharose 6B-C1, and wheat germ agglutinin-Sepharose 4B columns, the pNPPase activity coeluted with the phosphotyrosyl histone phosphatase activity, and was separable from the phosphoseryl histone phosphatase activity. The results from column chromatography also indicated that there may be multiple phosphotyrosyl and phosphoseryl protein phosphatases in the plasma membranes.
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U2 - 10.1016/0003-9861(85)90694-0
DO - 10.1016/0003-9861(85)90694-0
M3 - Article
C2 - 2408568
AN - SCOPUS:0022261802
SN - 0003-9861
VL - 239
SP - 320
EP - 326
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 2
ER -