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The molecular size required varies according to the reaction step round the sodium pump cycle
Author(s) -
Cavieres J.D.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81147-x
Subject(s) - sodium pump , sodium , chemistry , atpase , protein subunit , biophysics , atp synthase , biochemistry , enzyme , biology , ouabain , organic chemistry , gene
Progress along the path of the sodium pump cycle requires a stepwise recruitment of additional subunits for maximal activity. These results show that whereas a particle the size of the αβ protomer presents Na + ,K + ‐ATPase activity at 10 μM ATP, an additional subunit, perhaps a second α‐chain, is required to obtain the much greater Na + ,K + ‐ATPase activity resulting from the occupation of low‐affinity ATP sites at physiological ATP concentrations. A non‐phosphorylating ATP analogue, however, will modestly stimulate the Na + ,K + ‐ATPase activity acting at an alternative low‐affinity site or step on the αβ protomer.