ISOELECTRIC-FOCUSING STUDIES OF CONCANAVALIN-A AND THE LENTIL LECTIN
ISOELECTRIC-FOCUSING STUDIES OF CONCANAVALIN-A AND THE LENTIL LECTIN
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DOI：
10.1016/s0021-9673(01)89570-4
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发表时间：
1990-02-21
期刊：
影响因子：
--
通讯作者：
BREWER, CF
中科院分区：
文献类型：
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作者：
BHATTACHARYYA, L;BREWER, CF
由完整亚基和碎片亚基组成的金属化和去金属化刀豆蛋白A （cona）的等电聚焦（IEF）表现出不同的波段模式。由完整多肽链组成的金属化Con A（完整Con A）具有等电点（pI） 8.35。由碎片链组成的金属化制剂（碎片化Con A）显示出3个波段，pI值分别为8.0、7.8和7.7。去金属化完好Con A（完好apoon A）的pI为6.5，但在一定条件下，它在IEF过程中发生pH依赖性缔合，从而产生多波段。在pH范围为3至10的两性电解质存在的情况下，在IEF期间，两性电解质介导的完整和碎片化的Con A的脱金属和随后载脂蛋白的聚集导致多个条带。然而，pH值范围为7至9的两性水解液不会使蛋白质脱金属，并显示出具有完整Con a的单带。在抑制糖存在的情况下，完整Con a的pI基本保持不变。此外，我们还鉴定了Con A的不同分子形态，包括完整的apoon A的锁定和解锁构象，以及完整Con A和完整apoon A的二聚体和四聚体状态，并确定了它们的pI值。LcH-A和LcH-B等选素的IEF值分别为pI 8.5和9.0。然而，天然凝集素混合物产生了额外的pI 8.8波段，这是由于在分离凝集素之间通过两性聚合物介导的亚基交换形成的杂交蛋白。
Isoelectric focusing (IEF) of metallized and demetallized preparations of concanavalin A (Con A) consisting of either intact or fragmented subunits shows different band patterns. Metallized Con A consisting of intact polypeptide chains (intact Con A) has an isoelectric point (pI) 8.35. Metallized preparations consisting of fragmented chains (fragmented Con A) show the three bands with pI values 8.0, 7.8 and 7.7. Demetallized intact Con A (intact apoCon A) has a pI of 6.5, however, it undergoes pH dependent association during IEF under certain conditions, which gives rise to multiple bands. Ampholyte-mediated demetallization of intact and fragmented Con A and subsequent aggregation of the apoprotein results in multiple bands during IEF in the presence of the pH range 3 to 10 ampholytes. However, ampholytes of the pH range 7 to 9 do not demetallize the proteins and show a single band with intact Con A. The pI of intact Con A remains essentially the same in the presence of inhibitory sugar. Furthermore, different molecular forms of Con A, including locked and unlocked conformers of intact apoCon A, and the dimeric and tetramic states of both intact Con A and intact apoCon A have been identified and their pI values determined. IEF of the lentil isoelectins, LcH-A and LcH-B, shows single bands of pI 8.5 and 9.0, respectively. However, the native lectin mixture gives rise to an additional band of pI 8.8 due to a hybrid protein formed by ampholyte-mediated subunit exchange between the isolectins.