COMPARATIVE STUDY OF PHOSPHOTYROSYL PROTEIN PHOSPHATASE OF MICE NORMAL LIVER, REGENERATING LIVER, AND MICE H22A HEPATOMA ASCITES CELL

In regenerating liver of mice, marked increase of the activity of phosphotyrosyl protein phosphatase (PTPP) in cytosol was observed. The PTPP activity varied with time and reached the highest level between 24 to 48 hours after partial hepatectomy. In H22a cells the PTPP activity found in every subcellular fraction was lower than that of the normal liver. The PTPP activity was mostly concentrated in lysosomes of normal liver, but mainly distributed in nucleus, cytosol and microsome of regenerating liver. In H22a cells PTPP activity seemed distribute evenly. Five similar major PTPP peaks (I-V) were obtained on DEAE cellulose chromatography of cytosols from all three of liver cells studied. However, two additional PTPP peaks, a and b, were also obtained from cytosol of liver.

小鼠肝癌H_(22)细胞LDL受体活性的研究

目的 :观察小鼠肝癌H2 2 细胞LDLR活性。方法 :对小鼠肝癌H2 2 细胞和正常肝细胞进行受体结合的Scatchard分析和单点分析。结果 :①H2 2 细胞对LDL的亲和性与正常肝细胞相同 ,但H2 2 细胞Bmax明显增多 ;②H2 2 细胞对LDL的非特异性结合、内移和降解能力与正常肝细胞相同。结论 :小鼠肝癌H2 2 细胞LDLR活性增高 ,其对LDL的内移和降解功能未变。

小鼠肝癌H_(22)细胞LDLR的分析研究

目的 :观察分析小鼠肝癌 H2 2 细胞及正常肝细胞低密度脂蛋白受体 (L DL R)对低密度脂蛋白 (L DL)的结合。方法 :用 1 2 5 I标记 L DL ,对小鼠肝癌 H2 2 细胞及正常肝细胞 L DL R进行受体饱和分析。结果 :H2 2 细胞及正常肝细胞主要通过其 L DL R结合 L DL。 H2 2 细胞及正常肝细胞 L DL R对 L DL的亲和性和特异性相同 ,但 H2 2 细胞Bmax明显增多。结论 :小鼠肝癌 H2 2 细胞 L DL R数目增多 。