7S globulin from soybean is metabolized in human cell cultures by a specific uptake and degradation system.
7S globulin from soybean is metabolized in human cell cultures by a specific uptake and degradation system.
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大豆中的 7S 球蛋白在人体细胞培养物中通过特定的吸收和降解系统进行代谢。
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
C. Sirtori
中科院分区：
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作者：
M. Lovati;C. Manzoni;Alberto Corsini;A. Granata;R. Fumagalli;C. Sirtori
我们研究了来自大豆的7S球蛋白在肝癌细胞系（Hep G2）和人皮肤成纤维细胞（HSF）中的生物学命运，以获得对7S球蛋白细胞过程的新见解，其最终效果是LDL受体的表达增强。在不同的实验条件下，7S球蛋白的结合能力，并被内化和降解的两种细胞类型进行了研究。在所有情况下，125 I-7S球蛋白的特异性摄取（结合+内化）和降解是37 ℃下底物浓度的曲线函数。这两个过程在80 mg/L左右达到饱和，这是先前报道的LDL受体上调的浓度。125 I-7S球蛋白的特异性摄取在37 ℃时是时间的曲线函数，并分别在HSF和Hep G2细胞中在6和12 h后达到平衡。在4 ℃下在Hep G2细胞中进行的结合实验显示7S球蛋白与细胞膜的特异性和可饱和缔合。线性Scatchard分析证明了单一的结合位点群体。饱和时结合的7S球蛋白量（Bmax）约为2.73 mg/L，表观Kd为21 μ mol/L，假定7S球蛋白分子量为175 kDa。Hep G2膜蛋白与125 I-7S球蛋白孵育的SDS-PAGE显示7S球蛋白与分子量在14和21 kDa之间的细胞蛋白组分特异性相互作用。需要进一步研究以确定这种相互作用是否与观察到的LDL受体刺激直接或间接相关。
We examined the biological fate of 7S globulin from soybean in a hepatoma cell line (Hep G2) and in human skin fibroblasts (HSF) to gain new insights into the 7S globulin cell process, the final effect of which is an enhanced expression of the LDL-receptor. The ability of 7S globulin to bind and to be internalized and degraded by both cell types was investigated under different experimental conditions. In all cases, specific uptake (binding + internalization) and degradation of 125I-7S globulin were curvilinear functions of substrate concentration at 37 degrees C. The two processes were saturated at around 80 mg/L, a concentration at which an up-regulation of LDL-receptor was previously reported. The specific uptake of 125I-7S globulin at 37 degrees C was a curvilinear function of time, and achieved equilibrium after 6 and 12 h in HSF and Hep G2 cells, respectively. Binding experiments, conducted at 4 degrees C in Hep G2 cells, showed a specific and saturable association of 7S globulin to the cell membrane. Linear Scatchard analysis demonstrated a single population of binding sites. The amount of 7S globulin bound at saturation (Bmax) was about 2.73 mg/L, with an apparent Kd of 21 micromol/L, assuming 175 kDa as the 7S globulin molecular weight. SDS-PAGE of Hep G2 membrane proteins incubated with 125I-7S globulin revealed a specific interaction of 7S globulin with a cell protein component with molecular weight between 14 and 21 kDa. Further studies are needed to ascertain whether this interaction is directly or indirectly related to the observed stimulation of the LDL-receptor.