Some
properties of particle-bound intracellular ATPase from baker's
yeast
Bennun, A., De Pahn, E.M. and Stoppani, A.O.M.
A particle-bound, Mg2+, DNP-activated ATPase has been obtained
from baker's yeast (fresh or dried) by mechanical disintegration
and differential centrifugation of the cell extract. The isolated
fraction hydrolyses ATP, GTP and ITP but is not effective
with CTP. ADP inhibits the hydrolysis of ATP and ITP; IDP
does not. The addition of an ADP-trapping system prevents
the inhibitory action of ADP and keeps the rate of hydrolysis
of ATP linear. ATPase activity is released by Mg2+ and Mn2+
but not by Ca2+. In the presence of 2.5 mM Mg2+, maximum activity
is at pH 9.0-9.5 DNP produces significant activation of the
enzyme with ATP as substrate but not with GTP, CTP or ITP;
the stimulation of ATPase by DNP is most effective at pH 5.5-6.5.
In the presence of Mg2+, 50 mM fluoridc inhibits, by 53%,
the enzymic activity. The properties of the particle-bound
ATPase are considered in relation to the surface-located,
and soluble, yeast ATPases and animal mitochondrial ATPase.
Biochimica et
Biophysica Acta, 89, (1964), 532-539