BINDING OF INSULIN-RECEPTORS TO LECTINS - EVIDENCE FOR COMMON CARBOHYDRATE DETERMINANTS ON SEVERAL MEMBRANE-RECEPTORS
BINDING OF INSULIN-RECEPTORS TO LECTINS - EVIDENCE FOR COMMON CARBOHYDRATE DETERMINANTS ON SEVERAL MEMBRANE-RECEPTORS
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DOI：
10.1021/bi00515a013
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发表时间：
1981-01-01
期刊：
影响因子：
2.9
通讯作者：
ROTH, J
中科院分区：
文献类型：
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作者：
HEDO, JA;HARRISON, LC;ROTH, J
将人胎盘和培养的淋巴细胞（IM-9系）的胰岛素受体溶解在Triton X-100中，并应用于含有12种不同固定化凝集素的琼脂糖柱。两种组织的受体被凝集素吸附，结合N-乙酰葡糖胺（小麦胚芽），甘露糖（伴刀豆球蛋白A，扁豆和豌豆）和半乳糖（蓖麻蛋白I和II），但不保留凝集素结合N-乙酰半乳糖胺（马革，国槐和大豆），岩藻糖（金雀花种子I）和半乳糖（Bandieraea simplicifolia和花生）。用适当的单糖解吸后，受体的胰岛素结合能力增加5- 50倍，回收率为7- 98%。当将来自两种组织的溶解的膜依次在3个不同的凝集素柱（例如，小麦胚芽、小扁豆和蓖麻毒素I），从第2和第3柱洗脱后，受体的纯度仅略有增加。增殖刺激活性（MSA）和表皮生长因子（EGF）在溶解的胎盘膜受体的行为非常相似的胰岛素受体上连续凝集素色谱。从凝集素柱洗脱后，受体亲和力明显增加，如未标记胰岛素浓度降低所证明，导致[125 I]胰岛素结合的半数最大降低，结合/游离[125 I]胰岛素（示踪剂结合）的增加大于结合能力（饱和结合）的增加。这种亲和力的变化是渐进的顺序凝集素层析。胰岛素受体的碳水化合物部分显然含有N-乙酰葡糖胺、甘露糖和半乳糖，但这些糖残基既不是受体特异性也不是组织特异性的。胰岛素受体从凝集素解吸后亲和力的增加可能是由于与相关亲和力调节剂（抑制剂）的结合位点分离。
Insulin receptors from human placenta and from cultured lymphocytes (IM-9 line) were solubilized in Triton X-100 and applied to agarose columns containing 12 different immobilized lectins. Receptors from both tissues were adsorbed by lectins that bind N-acetylglucosamine (wheat germ), mannose (concanavalin A, lentil and pea) and galactose (ricins I and II) but were unretained by lectins that bind N-acetylgalactosamine (horse gram, Sophora japonica and soybean), fucose (gorse seed I) and galactose (Bandieraea simplicifolia and peanut). After desorption with the appropriate monosaccharides, the insulin-binding capacity of the receptor was increased between 5- and 50-fold with recoveries ranging from 7-98%. When the solubilized membranes from both tissues were chromatographed sequentially on 3 different lectin columns (e.g., wheat germ, lentil and ricin I), the receptor showed only a minor increase in purity after elution from the 2nd and 3rd columns. Receptors for multiplication-stimulating activity (MSA) and epidermal growth factor (EGF) in the solubilized placental membranes behaved very similarly to insulin receptors on sequential lectin chromatography. Elution from the lectin columns was followed by a clear increase in the affinity of the receptors as evidenced by a decrease in the concentration of unlabeled insulin, causing half-maximal reduction of [125I]insulin binding, and an increase in bound/free [125I]insulin (tracer binding) greater than the increase in binding capacity (saturation binding). This affinity shift was progressive on sequential lectin chromatography. The carbohydrate moiety of the insulin receptor apparently contains N-acetylglucosamine, mannose and galactose but these saccharide residues are neither receptor- nor tissue-specific. The increase in affinity of the insulin receptor after its desorption from lectins may be due to separation from the binding site of an associated affinity regulator (inhibitor).