Le Rumeur E, Winchenne J J, Boffa G A, Nadal C
Cell Tissue Kinet. 1983 Jul;16(4):333-42.
The properties were investigated of low molecular weight factors acting on the G1-S transition of baby rat hepatocytes. These factors were produced by incubating adult rat serum with trypsin or a 100,000 g liver microsomal fraction, and isolated by ultrafiltration. Enzyme degradation assays indicated that the active compound was in both cases a glycopeptide sensitive to pronase and papain and to the combination of neuraminidase and beta galactosidase. No loss of hepatocyte G1-S inhibitory activity was observed after heat treatment at pH 7.0. G50 gel filtration showed that both the G1-S inhibitory factors were collected in the last fractions eluted. The elution volume was slightly larger for the trypsin than for the microsomal-induced factor, suggesting a small difference between their molecular weight. These factors are believed to be glycopeptides with a molecular weight around 1400. They might be composed of a 3-sugar polysaccharide chain with a galactose preterminal and a neuraminic acid terminal, linked to a polypeptide chain of 6 to 8 amino acids.
对作用于新生大鼠肝细胞G1-S期转换的低分子量因子的特性进行了研究。这些因子是通过将成年大鼠血清与胰蛋白酶或100,000g肝脏微粒体部分孵育产生的，并通过超滤进行分离。酶降解试验表明，在两种情况下，活性化合物都是对链霉蛋白酶、木瓜蛋白酶以及神经氨酸酶和β-半乳糖苷酶的组合敏感的糖肽。在pH 7.0下热处理后，未观察到肝细胞G1-S抑制活性的丧失。G50凝胶过滤显示，两种G1-S抑制因子都收集在洗脱的最后部分。胰蛋白酶诱导的因子的洗脱体积比微粒体诱导的因子略大，表明它们的分子量存在微小差异。这些因子被认为是分子量约为1400的糖肽。它们可能由一个具有半乳糖前末端和神经氨酸末端的三糖多糖链组成，该链与一个由6至8个氨基酸组成的多肽链相连。
