Differences in α‐amino acetylation of isozymes of yeast alcohol dehydrogenase
Differences in α‐amino acetylation of isozymes of yeast alcohol dehydrogenase
复制标题
酵母乙醇脱氢酶同工酶α-氨基乙酰化的差异
DOI：
10.1016/0014-5793(80)80796-4
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发表时间：
1980
期刊：
影响因子：
3.5
通讯作者：
C. Wills
中科院分区：
文献类型：
--
作者：
H. Jörnvall;T. Fairwell;P. Kratofil;C. Wills
天然蛋白质和多肽通常含有乙酰基封闭的油氨基。这种N末端修饰最初是在病毒外壳蛋白[I]和荷尔蒙多肽[2]中发现的，但现在已知是非常常见的，影响到许多类别的自然产生的多肽链[3]。蛋白质通常以完全封闭的形式回收[3]，并用乙酰CUA在新生多肽链上进行酶促修饰[4]。在无细胞系统中，通过人工去除乙酰辅酶A可以防止翻译过程中的堵塞[5]。然而，一旦连接起来。牛乙酰基相对惰性[6]。乙酰化的功能意义尚不清楚，但已被认为可以防止过早的蛋白质分解代谢[3]。酒精脱氢酶通常有一个被酰基阻断的N末端[7]。因此，这种蛋白质很可能是乙酰化的，但直到本报告才直接显示出来。在对这两种主要同工酶的研究中，人们发现，在某些生理条件下，蛋白质包涵体的N-末端也可以以不受阻止的形式恢复[8]。虽然同工酶的分离是不完整的，但未被阻断的分子的存在似乎与生长条件和同工酶图谱有关。由于封闭的和未封闭的(乙酰化和非乙酰化)分子都具有活性，这一发现为研究乙酰化在蛋白质代谢和酶功能中的可能作用提供了机会。
Native proteins and peptides often have acetylblocked oi-amino groups. This N-terminal modification was first discovered in a viral coat protein [I] and a hormonal peptide [2] but is now known to be very common, affecting many classes of naturally occurring polypeptide chains [3]. The proteins are usually recovered m completely blocked form [3], and the modification is enzymatically performed on the nascent polypeptide chain with acetyl-CuA [4]. The blockage can be prevented during translation in cellfree systems by artificial removal of acetyl-CoA [5]. Once attached, however. the Niu-acetyl group is comparatively inert [6]. The functional significance of acetylation is unknown, but it has been suggested that it may protect against premature protein catabolism [3].Yeast alcohol dehydrogenase normally has an acyl-blocked N-terminus [7]. Acetylatlon of this protein was therefore likely but not directly shown until the present report. During studies of the two major lsozymes, it was discovered that the N-terminus of the protein subumts may also be recovered in unblocked form under certain physiological conditions [8]. Although isozyme separations wer-e incomplete, the presence of unblocked molecules appeared to be associated with growth conditions and isozyme patterns. Since both blocked and unblocked (acetylated and unacetylated) molecules have activity, this finding provided an opportunity to investigate the possible roles of acetylation in protein metabolism and enzyme function.