A new member of the ATPase family

Abstract

Raterythrocyte ghosts have an ATPASE activity which is Mg dependent, Na activated, but K inhibited. The Na activation is completely inhibited by cardiac glycosides. The glycoside inhibition is, in turn, blockedby K. Caalso inhibits the Naactiva-tion of this ATPase. ThisATPase is seenonlyatlow concentrations of ATP substrate and has a Km of 2.2 x 10-7 [image] ATP/liter. The possibilities that it may be involved in the facilitated transport of hexoses and of amino acids are suggested as is the possibility that it may be involved in a noncoupled Na transport.