Inositol trisphosphate‐mediated Ca2+ release in beet mu;somes is inhibited by heparin

[摘要]

Microsomes from the storage root of red beet exhibit ATP-dependent, protonophore-sensitive Ca²⁺ accumulation, characteristic of the vacuolar membrane (tonoplast). A portion (20%) of this intravesicular Ca²⁺ store is specifically released by inositol 1,4,5-trisphosphate (InsP₃) with a K _0.5 = 0.54 μM. InsP₃,-mediated Ca²⁺ release is eliminated by low concentrations of heparin (K _0.5 = 86 nM). This result highlights the conservation between the animal and plant inositol 1,4,5-trisphosphate-mediated Ca²⁺ release mechanisms, despite the fact that they are located at different intracellular membranes.

[学科分类] 生物化学/生物物理

[关键词] Tonoplast;Calcium efflux;Inositol 1;4;5-trisphosphate;Heparin;(Beta vulgaris);BTP;1;3-bisltris(hydroxymethyl)methylamino]-propane;InsP3;inositol 1;4;5-trisphosphate;InsP2;inositol 1;4-bisphosphate;InsP4;inositol 1;3;4;5-tetrakisphosphate;TMB-8;8-(N;N-diethylamino)-octyl 3;4;5-trimethoxybenzoate-HCl;FCCP;carbonylcyanide p-trifluoromethoxyphenylhydrazone