Spontaneous alterations in the covalent structure of synapsin I during in vitro aging.
Spontaneous alterations in the covalent structure of synapsin I during in vitro aging.
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体外老化过程中突触蛋白 I 共价结构的自发改变。
DOI：
10.1006/bbrc.1995.1989
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Aswad,DW
中科院分区：
文献类型：
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作者：
Paranandi,MV;Aswad,DW
将从牛脑纯化的突触蛋白I在pH 7.4和37°C下孵育30天。在不同时间取样，并使用蛋白质-L-异戊酰基甲基转移酶测定异天冬氨酸含量。在最初的22天内，突触蛋白以每100个突触蛋白分子每天≥ 6个位点的速率积累异戊酰位点。伴随着异天冬氨酸形成，突触蛋白经历了其他两种类型的修改：通过形成二硫键的自发分子间交联的程度很大，和第二个，不太明显，不可逆的聚集。不可逆聚集显然是由非二硫化物性质的共价交联或可能是强疏水相互作用引起的。在体外老化过程中，异天冬氨酸在突触蛋白的聚集和非聚集形式中积累。这些发现表明突触蛋白在生理条件下能够发生显著的自发共价改变。这些修饰可能在体内突触蛋白的功能中起作用，或限制突触蛋白的寿命。
Synapsin I purified from bovine brain was incubated for 30 days at pH 7.4 and 37°C. Samples were taken at various times and assayed for isoaspartate content using protein-L-isoaspartyl methyltransferase. During the first 22 days, synapsin accumulated isoaspartyl sites at a rate of ≥ 6 sites per day per 100 molecules of synapsin. Concomitant with isoaspartate formation, synapsin underwent two other types of modification: a substantial degree of spontaneous intermolecular cross-linking via the formation of disulfide bonds, and a second, less pronounced, irreversible aggregation. The irreversible aggregation apparently results from covalent cross-linking of a non-disulfide nature or possibly a strong hydrophobic interaction. Isoaspartate accumulated in both aggregated and non-aggregated forms of synapsin during in vitro aging. These findings demonstrate that synapsin is capable of significant spontaneous covalent alteration under physiological conditions. These modifications may play a role in the function of, or limit the lifetime of, synapsin in vivo.