Several compartments of Saccharomyces cerevisiae are equipped with Ca(2+)-ATPase(s)
Sucrose density fractionation of yeast membranes revealed two major and two minor peaks of 45Ca2+ transport activity which all co-migrate with marker enzymes of the endoplasmic reticulum, Golgi and membranes associated with these compartments as well as with ATPase activity measured when all other known ATPase are inhibited. Co-migration of 45Ca2+ transport and ATPase activities was also found after removal of plasma membranes by concanavalin A treatment. SDS-PAGE at pH 6.3 shows the Ca(2+)-dependent formation of acyl phosphate polypeptides of about 110 and 200 kDa. It is concluded that several compartments or sub-compartments of yeast are equipped with Ca(2+)-ATPase(s). It is proposed that these compartments are derived from the protein secretory apparatus of yeast.
Okorokov
L A
LA
Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, Brazil.
D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000032:analysis*; D009251:NADPH-Ferrihemoprotein Reductase / Q000032:analysis; D011755:Pyrophosphatases / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D009251:NADPH-Ferrihemoprotein Reductase; D011755:Pyrophosphatases; C010357:guanosine-diphosphatase; D000252:Calcium-Transporting ATPases; D002118:Calcium