Details

Autor(en) / Beteiligte

• Krylova, Valeriya
• Andreev, Igor M
• Zartdinova, Rozaliya
• Izmailov, Stanislav F

Titel

Biochemical characteristics of the Ca²⁺ pumping ATPase in the peribacteroid membrane from broad bean root nodules

Ist Teil von

• Protoplasma, 2013-04, Vol.250 (2), p.531-538

Ort / Verlag

Vienna: Springer-Verlag

Erscheinungsjahr

2013

Quelle

MEDLINE

Beschreibungen/Notizen

• Ca²⁺-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 Ca²⁺ through the PBM by the Ca²⁺-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 Ca²⁺-ATPase for Ca²⁺ of about 0.1 μM. The transport activity of Ca²⁺-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 Ca²⁺-ATPases which are present in other plant membranes.