Kaiser A M, Wasner H K, Spindler K D
Diabetes-Forschungsinstitut, Düsseldorf, Germany.
Biol Chem. 1998 Jun;379(6):727-30.
The cyclic AMP antagonist, prostaglandylinositol cyclic phosphate (cyclic PIP), is synthesized from prostaglandin E (PGE) and activated inositol phosphate (n-IP) in the presence of ATP by an enzyme of rat liver plasma membranes. Extracts of the slime mould Dictyostelium discoideum contain this activated inositol phosphate and D. discoideum cells convert [3H]PGE1 to [3H]cyclic PIP. This extracted polar [3H]product co-chromatographed with cyclic PIP from rat liver on gel filtration, anion exchange- and adsorption chromatography. Starving D. discoideum cells show cyclic AMP-induced oscillations, which can be inhibited by cyclic PIP (0.4 x 10(-7) M), but not by its phosphomonoester prostaglandylinositol phosphate (PIP) (1.4 x 10(-7) M). AMP and ADP at much higher concentrations (1 mM) antagonized these oscillations. The time needed for aggregation and fruiting body formation of starving D. discoideum cells is extended by cyclic PIP (1.4 x 10(-7) M) up to 3-fold, whereas its phosphomonoester (1.9 x 10(-7) M) showed a 9-fold weaker effect, and AMP and ADP even at 1 mM concentration showed no effect.
环磷酸腺苷拮抗剂前列腺素肌醇环磷酸酯（环PIP）由前列腺素E（PGE）和活化的肌醇磷酸（n - IP）在ATP存在的情况下，通过大鼠肝细胞膜的一种酶合成。盘基网柄菌的提取物含有这种活化的肌醇磷酸，并且盘基网柄菌细胞能将[3H]PGE1转化为[3H]环PIP。这种提取的极性[3H]产物在凝胶过滤、阴离子交换色谱和吸附色谱上与大鼠肝脏的环PIP共色谱。饥饿的盘基网柄菌细胞表现出环磷酸腺苷诱导的振荡，这种振荡可被环PIP（0.4×10⁻⁷M）抑制，但不能被其磷酸单酯前列腺素肌醇磷酸（PIP）（1.4×10⁻⁷M）抑制。浓度高得多的AMP和ADP（1 mM）可拮抗这些振荡。饥饿的盘基网柄菌细胞聚集和形成子实体所需的时间被环PIP（1.4×10⁻⁷M）延长至3倍，而其磷酸单酯（1.9×10⁻⁷M）的作用弱9倍，即使浓度为1 mM的AMP和ADP也没有作用。
