Multiple thiamine-binding proteins of legume seeds. Thiamine-binding vicilin of Vicia faba versus thiamine-binding albumin of Pisum sativum
Multiple thiamine-binding proteins of legume seeds. Thiamine-binding vicilin of Vicia faba versus thiamine-binding albumin of Pisum sativum
复制标题
豆类种子的多种硫胺素结合蛋白。
DOI：
10.1016/s0981-9428(02)01428-6
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
A. Kozik
中科院分区：
文献类型：
--
作者：
S. Adamek;A. Kozik
硫胺素结合蛋白广泛存在于植物种子中，但在豆类种子中尚未被描述，另一方面，豆类种子中的一般贮藏蛋白在结构和功能上是已知的。在这项工作中，我们发现几种豆科植物种子中的硫胺素结合活性分布在球蛋白和白蛋白两个组分之间。从蚕豆中分离到一种具有7S贮藏球蛋白典型分子特性的硫胺素结合蛋白(TBP)。种子。它的分子质量为150-170 kDa，是一种含有50和27 kDa亚基的低聚物。它结合硫胺素的解离常数为1.3GμM，与其他被子植物硫胺素结合球蛋白的解离常数相当。豌豆(Pisum Sativum L.)种子除了含有类似的硫胺素结合蛋白外，还含有一种较小的TBP，它是24 kDa亚基的二聚体。它的分子特征与一种被命名为PA2的主要豌豆白蛋白非常相似。具体来说，TBP N-末端的前35个氨基酸的序列与PA2白蛋白的序列完全匹配。这种硫胺素结合蛋白以低亲和力(解离常数35μM)结合硫胺素。豆类种子的硫胺素结合蛋白可能代表硫胺素的储存功能，但白蛋白所属的硫胺素结合的意义仍有待确定。
Thiamine-binding proteins ubiquitously occur in plant seeds but they have not been characterised in legume seeds where, on the other hand, the general storage proteins are known in structural and functional detail. In this work, we show that thiamine-binding activity in seeds of several leguminous species is distributed between both globulin and albumin fractions. A thiamine-binding protein (TBP) with molecular properties typical of 7S storage globulin (vicilin) is isolated from broad bean (Vicia faba L.) seeds. It has a molecular mass of 150–170 kDa and is an oligomer containing 50 and 27 kDa subunits. It binds thiamine with a dissociation constant of 1.3 μM comparable to that of other angiosperm thiamine-binding globulins. Garden pea (Pisum sativum L.) seeds contain, in addition to a similar thiamine-binding vicilin, a smaller TBP which is a dimer of 24 kDa subunits. Its molecular characteristics are very similar to those of a well-characterised major pea albumin designated PA2. Specifically, the sequence of the first 35 amino acids from the N-terminus of TBP exactly matches that of PA2 albumin. This thiamine-binding protein binds thiamine with a low affinity (dissociation constant of 35 μM). Thiamine-binding vicilins of legume seeds probably represent a thiamine-storage function but a significance of the albumin-attributable thiamine binding remains to be determined.