SITE-SPECIFIC N-TERMINAL AUTO-DEGRADATION OF HUMAN SERUM-ALBUMIN
SITE-SPECIFIC N-TERMINAL AUTO-DEGRADATION OF HUMAN SERUM-ALBUMIN
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DOI：
10.1111/j.1432-1033.1995.tb20419.x
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发表时间：
1995-01-15
期刊：
影响因子：
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通讯作者：
HARRIS, R
中科院分区：
文献类型：
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作者：
CHAN, B;DODSWORTH, N;HARRIS, R
临床上用血液分离法制备的人血清白蛋白，在30 ℃或30 ℃以上储存时会发生降解。蛋白质的质谱和N-末端测序鉴定了与前两个残基天冬氨酸和丙氨酸的丢失相对应的降解。该反应被证明是依赖于温度和N-末端α-氨基。此外，与来自其他物种的血清白蛋白的比较表明，N-末端的不稳定性是特异性的人白蛋白序列。从降解的白蛋白溶液中纯化的完整的乙酰丙氨酰二肽在氨基酸分析、N-末端测序和NMR上与合成二肽有很大不同。这表明，释放的二肽可能是环状的，这意味着一种新的切割机制。
Human serum albumin prepared by blood fractionation for clinical purposes was found to degrade when stored at or above 30 degrees C. Mass spectrometry and N-terminal sequencing of the protein identified degradation corresponding to the loss of the first two residues, aspartic acid and alanine. The reaction was shown to be dependent upon temperature and the N-terminal alpha-amino group. In addition, comparison with serum albumins derived from other species showed that the instability of the N-terminus was specific to the human albumin sequence. An intact aspartyl-alanyl dipeptide, purified from degraded albumin solutions, differed substantially from a synthetic dipeptide on amino acid analysis, N-terminal sequencing and NMR. It is suggested that the released dipeptide may be cyclic, implying a novel cleavage mechanism.