中文摘要：

研究了在人神经母细胞瘤株SH—SY5Y中calcineirin比活性测定的最佳条件．以RⅡ为底物，在测活缓冲液中，Ca^2＋和岗田酸（okadaic acid，OA）的加入是必须的，这与在脑组织中的测定是不一样的，同时进一步确定了需要加入的OA是100nmol·L^-1．在细胞破碎液中，calcineurin比活性的测定值是以缓冲液Ⅰ（含Ca^2＋与OA）中测得CN比活性数值减去缓冲液Ⅱ（含EGTA与OA）中所测比活性数值之差来表示．

英文摘要：

Effects of Ca^2＋ and OA on calcineurin （CN） activity in SH-SY5Y cell extracts were investigated with RⅡ phosphopeptide as substrate. Data showed that adding Ca^2＋ to assay buffer Ⅰ was necessary to activate CN in SH-SY5Y cell extracts, which was unlike extracts from brain. Further, it was necessary to add OA to assay buffers to inhibit PP1 and PP2A in SH-SY5Y cell extracts, with an optimal OA concentration of 100 nmol.L^-1, which was also unlike the brain extracts. In conclusion, calcineurin phosphatase activity in SH-SY5Y cell extracts should be calculated as the difference in protein phosphatase activity in buffer Ⅰ （cantains Ca^2＋ and OA） and buffer Ⅱ （cantains EGTAand OA）＂.