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GTP causes calcium release from a plant microsomal fraction

1989; Elsevier BV; Volume: 1; Issue: 1 Linguagem: Inglês

10.1016/0898-6568(89)90017-x

1873-3913

Elizabeth Allan, Alan P. Dawson, Drøbak Bjørn, Keith Roberts,

Photosynthetic Processes and Mechanisms

Studies on a variety of animal cell types have revealed a GTP-specific calcium-releasing mechanism in a non-mitochondrial, microsomal fraction. Here we report that GTP also induces rapid release of calcium from a zucchini (Cucurbita pepo L.) hypocotyl microsomal fraction. Maximal release occurs at 50 microM, and half-maximal release at 8 microM GTP. GTP is highly specific in its effect, and may not be replaced by UTP, ATP, CTP, TTP, GMP, or by non-hydrolysable analogues of GTP. Reuptake of calcium after release does not normally occur; however, this may be induced by non-hydrolysable GTP analogues. Calcium release is also blocked by prior treatment with these analogues.