CONTROLLED PROTEOLYSIS ACTIVATES THE PLASMA-MEMBRANE CA2+ PUMP OF HIGHER-PLANTS - A COMPARISON WITH THE EFFECT OF CALMODULIN IN PLASMA-MEMBRANE FROM RADISH SEEDLINGS

被引：0

作者：

CALDOGNO, FR ^{[1
]}

CARNELLI, A ^{[1
]}

DEMICHELIS, MI ^{[1
]}

机构：

[1] UNIV MESSINA,IST BOT,MESSINA S AGATA,ITALY

来源：

PLANT PHYSIOLOGY | 1993年 / 103卷 / 02期

关键词：

D O I：

暂无

中图分类号：

Q94 [植物学];

学科分类号：

071001 ;

摘要：

The effects of calmodulin and of controlled trypsin treatments on the activity of the Ca2+ pump were investigated in plasma membrane purified from radish (Raphanus sativus L.) seedlings. Treatment of the plasma membrane with ethylenediaminetetraacetate (EDTA), which removed about two-thirds of the plasma membrane-associated calmodulin, markedly increased the stimulation of the Ca2+ pump by calmodulin. In EDTA-treated plasma membrane, stimulation by calmodulin of the Ca2+ pump activity was maximal at low free Ca2+ (2-5 mum) and decreased with the increase of free Ca2+ concentration. The Ca2+ pump activity was stimulated also by a controlled treatment of the plasma membrane with trypsin: the effect of trypsin treatment depended on the concentration of both trypsin and plasma membrane proteins and on the duration of incubation. Stimulation of the Ca2+ pump activity by trypsin treatment of the plasma membrane was similar to that induced by calmodulin both in extent and in dependence on the free Ca2+ concentration in the assay medium. Moreover, the Ca2+ pump of trypsin-treated plasma membrane was insensitive to further stimulation by calmodulin, suggesting that limited proteolysis preferentially cleaves a regulatory domain of the enzyme that is involved in its activation by calmodulin.

引用

页码：385 / 390

页数：6

共 29 条

[1] RECONSTITUTION AND CHARACTERIZATION OF A CALMODULIN-STIMULATED CA-2+-PUMPING ATPASE PURIFIED FROM BRASSICA-OLERACEA L [J].