Gullis R J, Rowe C E
Biochem J. 1975 Jun;148(3):567-81. doi: 10.1042/bj1480567.
Hydrolysis of phosphatidylcholine by phospholipase A2 of synaptic membranes i n Tris-CHl buffer was stimulated by cyclic AMP, cyclic GMP, cyclic CMP, cyclic UMP and adenosine (0.1 mm). In the presence of 1 mm-NaF and cofactors, the same cyclic nucleotides and adenosine (10 mm) stimulated the incorporation of added oleate into the choline glycerophospholipids of synaptic membranes. Cyclic AMP and noradrenaline stimulated the incorporation of added oleate into position 2 of choline glycerophospholipid. Stimulation of net acylation was increased by preincubation in conditions which stimulated hydrolysis of phosphatidylcholine. Cyclic AMP only slightly stimulated the transfer of oleate from oleoyl-CoA into choline glycerophospholipid. The optimum concentration of CaCl2 for the stimulation of hydrolysis by phospholipase A2 by cyclic AMP was 1 mum. Stimulation of the incorporation of added oleate was maximal in the CaCl2 concentration range 1 mum-1mm. MgCl2 also enhanced stimulations, maximum effects being obtained with concentrations of 10 mum and 0.5 mm for hydrolysis by phospholipase A2 and incorporation of added oleate respectively. ATP enhanced the stimulation of incorporation of oleate but had no effect on the cyclic nucleotide stimulation of hydrolysis of added phosphatidylcholine by phospholipase A2. Adenosine, guanosine, ADP and 5'-AMP (all at 1 mm) inhibited the stimulation of incorporation of oleate by cyclic nucleotides and inhibited the transfer of oleate from oleoyl-CoA to phospholipid. They did not inhibit the stimulation of hydrolysis of added phosphatidylcholine (by phospholipase A2) by cyclic nucleotides, but inhibited the stimulation by noradrenaline, acetylcholine, 5-hydroxytryptamine, dopamine (3,4-dihydroxyphenethylamine) and histamine. Preincubation of synaptic membranes in the water or buffer increased the net activity of phospholipase A2. Preincubation with a mixture of ATP and MgCl2 increased the initial rate of acylation of membrane lipid.
在Tris - HCl缓冲液中，环磷酸腺苷（cAMP）、环磷酸鸟苷（cGMP）、环磷酸胞苷（cCMP）、环磷酸尿苷（cUMP）和腺苷（0.1 mM）可刺激突触膜磷脂酶A2对磷脂酰胆碱的水解作用。在1 mM氟化钠和辅助因子存在的情况下，相同的环核苷酸和腺苷（10 mM）可刺激添加的油酸酯掺入突触膜的胆碱甘油磷脂中。环磷酸腺苷和去甲肾上腺素可刺激添加的油酸酯掺入胆碱甘油磷脂的2位。在刺激磷脂酰胆碱水解的条件下进行预孵育，可增强净酰化作用的刺激。环磷酸腺苷仅轻微刺激油酸酯从油酰辅酶A转移至胆碱甘油磷脂中。环磷酸腺苷刺激磷脂酶A2水解作用的氯化钙最佳浓度为1 μM。在氯化钙浓度范围为1 μM至1 mM时，添加的油酸酯掺入量的刺激作用最大。氯化镁也可增强刺激作用，磷脂酶A2水解作用和添加的油酸酯掺入作用的最大效应分别在浓度为10 μM和0.5 mM时获得。三磷酸腺苷（ATP）增强了油酸酯掺入的刺激作用，但对环核苷酸刺激磷脂酶A2水解添加的磷脂酰胆碱没有影响。腺苷、鸟苷、二磷酸腺苷（ADP）和5'-单磷酸腺苷（5'-AMP）（均为1 mM）可抑制环核苷酸对油酸酯掺入的刺激作用，并抑制油酸酯从油酰辅酶A转移至磷脂。它们不抑制环核苷酸对添加的磷脂酰胆碱（由磷脂酶A2催化）水解的刺激作用，但抑制去甲肾上腺素、乙酰胆碱、5-羟色胺、多巴胺（3,4-二羟基苯乙胺）和组胺的刺激作用。突触膜在水中或缓冲液中预孵育可增加磷脂酶A2的净活性。用ATP和氯化镁的混合物进行预孵育可提高膜脂酰化的初始速率。
