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用差速离心及等密度梯度离心法从大白鼠心肌细胞分离收缩蛋白质及质膜,分别与[γ—~(32)P]ATP 保温以观察细胞成分的磷酸化,以及腺苷和腺苷类似物对磷酸化的影响。结果表明,在收缩蛋白质组分,~(32)P 主要参入肌钙蛋白 I(Troponin1,29000Da);在质膜组分,~(32)P 主要参入磷脂酰肌醇-4-一磷酸(Ptd Ins4P),亦即 TAP 使磷脂酰肌醇(PtdIns)磷酸化。腺苷对此两种磷酸化都有抑制作用,尤以对 Ptd Ins 磷酸化的抑制最强烈。cAMP 对肌钙蛋白 I 的磷酸化有剌激作用,这与文献报道相符。作者认为,腺苷和 cAMP 对肌钙蛋白 I 磷酸化的拮抗作用与腺苷和肾上腺素对心肌调节的拮抗作用有明显的相关性。鉴于近年发现,肌醇磷脂转换在调节细胞活动中起重要作用,腺苷对磷脂酰肌醇磷酸化的抑制作用可能有重要的生物学意义。
The contractile proteins and plasma membranes were isolated from rat cardiomyocytes by differential centrifugation and isopycnic gradient centrifugation, respectively, and incubated with [γ- (32) P] ATP to observe the phosphorylation of cellular components and adenosine and adenosine Effects of substances on phosphorylation. The results showed that ~ (32) P mainly participates in Troponin 1, 29000 Da in the contracted protein fraction, while P (32) P mainly participates in the interaction between Ptdtdin-4-monophosphate Ins4P), that is, TAP phosphorylates phosphatidylinositol (PtdIns). Adenosine inhibits both phosphorylations, with the strongest inhibition of Ptd Ins phosphorylation. cAMP stimulated the phosphorylation of troponin I, which is consistent with the literature. The authors believe that the antagonism of adenosine and cAMP on troponin I phosphorylation is significantly related to the antagonism of adenosine and epinephrine on myocardial regulation. In view of the recent discovery that inositol phospholipid conversion plays an important role in the regulation of cell activity, the inhibitory effect of adenosine on phosphatidylinositol phosphatiation may have important biological significance.