ALPHA,BETA-DEHYDRO-3,4-DIHYDROXYPHENYLALANINE DERIVATIVES - POTENTIAL SCHLEROTIZATION INTERMEDIATES IN NATURAL COMPOSITE-MATERIALS
ALPHA,BETA-DEHYDRO-3,4-DIHYDROXYPHENYLALANINE DERIVATIVES - POTENTIAL SCHLEROTIZATION INTERMEDIATES IN NATURAL COMPOSITE-MATERIALS
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DOI：
10.1016/0003-9861(91)90323-b
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发表时间：
1991-02-15
影响因子：
3.9
通讯作者：
WAITE, JH
中科院分区：
文献类型：
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作者：
RZEPECKI, LM;NAGAFUCHI, T;WAITE, JH
含有翻译后修饰的氨基酸-3，4-二羟基苯丙氨酸(DOPA)的蛋白质经过自动硬化，以确保在自然界中发现的许多结构基质中具有凝聚力。为了探索硬化的化学机制，我们考察了相对简单的多巴残基类似物的氧化产物，如N-乙酰多巴乙酯和N-乙酰多巴胺，以及几个寡肽的氧化产物。由两种儿茶酚氧化酶或高碘酸钠引起的氧化，导致路易斯碱催化形成不寻常的氨基酸3，4-二羟基-α，β-脱氢多巴(Δ多巴)的衍生物。以乙酰基Δ多巴乙酯为代表，用核磁共振和紫外光谱对其进行了表征。不同的多肽在氧化时产生类似的紫外光谱。在3，4-二羟基苯丙酸(二氢咖啡酸)氧化时也观察到类似的反应，但在n-乙酰多巴胺氧化后没有观察到类似的反应。有证据表明，这种转化是多巴对苯二酚部分重排为其Δ多巴互变异构体的结果，并且这种互变异构化可能是多肽多巴对苯二酚的主要命运，前提是有路易斯碱催化剂，竞争反应最小化。Δ多巴在天然或合成聚合物中的形成将增加可用于固化基质的交联剂的种类。在其他工作人员从几个海洋物种中分离出来的自然产生的寡肽中发现了Δ多巴。
Proteins containing the post-translationally modified amino acidl-3,4-dihydroxyphenylalanine (DOPA) undergo autosclerotization as a means of assuring cohesive resilience in many structural matrices found in nature. To explore the chemical mechanism of sclerotization, we examined the oxidation products of relatively simple analogs of a peptidyl DOPA residue, such asN-acetylDOPA ethyl ester andN-acetyldopamide, together with those of several oligopeptides. Oxidation, induced by either of two catecholoxidases or by sodium periodate, resulted in the Lewis base catalyzed formation of derivatives of the unusual amino acid 3,4-dihydroxy-α,β-dehydroDOPA (ΔDOPA). TheN-acetylΔDOPA ethyl ester representative of this group of derivatives was characterized by NMR and uv spectroscopy. A variety of peptides developed analogous uv spectra upon oxidation. A similar reaction was observed upon oxidation of 3,4-dihydroxyphenylpropanoic (dihydrocaffeic) acid, but not after oxidation ofN-acetyldopamine. Evidence is presented that this conversion is the result of a rearrangement of the DOPA quinone moiety to its ΔDOPA tautomer, and that this tautomerization can be a dominant fate for peptidyl DOPA quinone, provided a Lewis base catalyst is available and competing reactions are minimized. Formation of ΔDOPA in natural or synthetic polymers would increase the variety of crosslinks available to sclerotizing matrices. ΔDOPA has been found in naturally occurring oligopeptides isolated by other workers from several marine Species.