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Different Effects of Tris and Histidine on a Membrane Bound NaK ATPase from Sugar Beet Roots
Author(s) -
LINDBERG SYLVIA,
HALLMÉN GUN
Publication year - 1978
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1978.tb01604.x
Subject(s) - tris , dithiothreitol , chemistry , histidine , atpase , sugar beet , medicinal chemistry , biochemistry , enzyme , biology , horticulture
A membrane fraction of sugar beet roots prepared in the presence of dithiothreitol contains (Na + + K + + Mg 2+ ) ATPase activity. This activity was studied in the presence of different concentrations of Tris and histidine. Tris was found to interact with the ATPase in the following way: (1) Tris at 50 m M increases, in the absence of Na and/or K, the activity in an uncompetitive way with respect to MgATP. (2) Concentrations of Tris > 50 m M cause inhibition in the absence of Na and K when the ratio between MgATP and Tris is relatively low. (3) Though Tris at 50 m M stimulates similarly to Na, it can not substitute for Na in the Na + K activation. (4) In the presence of Na and K, Tris acts as a competitive inhibitor. Histidine has little influence on the rate both in the presence and absence of Na and/or K.