title: Biochemical characteristics of the Ca2+ pumping ATPase in the peribacteroid membrane from broad bean root nodules.
abstract: Ca(2+)-ATPase in the peribacteroid membrane (PBM) of symbiosomes isolated from Vicia faba root nodules was characterized in terms of its hydrolytic and transport activities. Both activities were found to be pH-dependent and exhibit pH optimum at pH 7.0. Translocation of Ca(2+) through the PBM by the Ca(2+)-ATPase was shown to be fueled by ATP and other nucleotide triphosphates in the following order: ATP > ITP ≅ GTP ≅ UTP ≅ CTP, the K m of the enzyme for MgATP being about 100 μM. Ca-dependent ITP-hydrolytic activity of symbiosomes was investigated in the presence of the Ca-EGTA buffer system and showed the affinity of PBM Ca(2+)-ATPase for Ca(2+) of about 0.1 μM. The transport activity of Ca(2+)-ATPase was inhibited by erythrosin B as well as orthovanadate, but markedly stimulated by calmodulin from bovine brain. These results allowed us to conclude that this enzyme belongs to IIB-type Ca(2+)-ATPases which are present in other plant membranes.
authors.affiliation: Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, 127276, Botanicheskaya st. 35, Russia. KrylovaVV@list.ru
authors.forename: Valeriya
authors.initials: V
authors.lastname: Krylova
authors.forename: Igor M
authors.initials: IM
authors.lastname: Andreev
authors.forename: Rozaliya
authors.initials: R
authors.lastname: Zartdinova
authors.forename: Stanislav F
authors.initials: SF
authors.lastname: Izmailov
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000965:Antimony / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology; D003570:Cytidine Triphosphate / Q000378:metabolism; D004923:Erythrosine / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism; D007293:Inosine Triphosphate / Q000378:metabolism; D053204:Root Nodules, Plant / Q000201:enzymology* / Q000378:metabolism*; D014544:Uridine Triphosphate / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D007293:Inosine Triphosphate; C009133:pyroantimonate; D014638:Vanadates; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D000965:Antimony; D000252:Calcium-Transporting ATPases; D004923:Erythrosine; D002118:Calcium; D014544:Uridine Triphosphate