Hancock J T, Maly F E, Jones O T
Department of Biochemistry, University of Bristol Medical School, U.K.
Biochem J. 1989 Aug 15;262(1):373-5. doi: 10.1042/bj2620373.
The capacity of three B-lymphocyte cell lines to generate superoxide (O2.-) was examined. The Burkitt lymphoma lines P.3HR-1 and Jijoye gave no response to phorbol 12-myristate 13-acetate (PMA) at 100 ng/ml but produced up to 0.35 nmol of O2.-/min per mg of protein when stimulated with 5 micrograms of PMA/ml; the cell line RPMI 1788 produced Nitro Blue Tetrazolium-positive responses to low PMA concentrations and approx. 0.4 nmol of O2.-/min per mg of protein at 5 micrograms of PMA/ml. Each cell line contained approx. 10 pmol of low-potential cytochrome b (cytochrome b-245)/mg of protein. Homogenates of PMA-activated cells gave 10-20-fold greater rates of O2.- produced per mg of protein. The Km for NADPH varied between approx. 250 microM for P3.HR-1 and RPMI 1788 cell lines and 30.5 +/- 6.5 microM for the Jijoye cell line; the Km values for NADH were higher. Determination of intracellular NADPH concentration showed that this might limit the rate of O2.- production since in each cell line it was at or below the Km concentration.
检测了三种B淋巴细胞系产生超氧化物（O2.-）的能力。伯基特淋巴瘤细胞系P.3HR-1和Jijoye对100 ng/ml的佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）无反应，但在5 μg/ml PMA刺激下，每毫克蛋白质每分钟可产生高达0.35 nmol的O2.-；细胞系RPMI 1788对低浓度PMA产生硝基蓝四氮唑阳性反应，在5 μg/ml PMA时，每毫克蛋白质每分钟产生约0.4 nmol的O2.-。每个细胞系每毫克蛋白质约含10 pmol的低电位细胞色素b（细胞色素b-245）。PMA激活细胞的匀浆每毫克蛋白质产生O2.-的速率高10 - 20倍。P3.HR-1和RPMI 1788细胞系中NADPH的Km约为250 μM，Jijoye细胞系中为30.5±6.5 μM；NADH的Km值更高。细胞内NADPH浓度的测定表明，这可能会限制O2.-的产生速率，因为在每个细胞系中，其浓度处于或低于Km浓度。
