Petrucci T, Sannia G, Parlamenti R, Silano V
Biochem J. 1978 Jul 1;173(1):229-35. doi: 10.1042/bj1730229.
Two wheat monomeric protein inhibitors of alpha-amylase with mol.wt. 12000, designated inhibitors 0.28 and 0.39 according to their gel-electrophoretic mobilities, showed almost identical circular-dichroism spectra in both the far and near u.v. at different pH values as well as in the presence or absence of dissociating and reducing agents. Both inhibitors (0.28 and 0.39) were readily inactivated by reduction of the five disulphide bridges present in each inhibitor molecule. These properties are very similar to those exhibited by the wheat dimeric protein inhibitor of alpha-amylase with mol.wt. 24000, designated inhibitor 0.19 according to its gel-electrophoretic mobility. The N-terminal sequence of the 0.19 inhibitor was determined without separating its subunits and compared with that of the 0.28 inhibitor reported by Redman [(1976) Biochem. J. 155, 193--195]. Petide 'maps' from tryptic digests of reduced and carboxymethylated inhibitors 0.19 and 0.28 were compared. One molecule of reducing sugar is covalently bound per inhibitor-0.19 protomer and inhibitor-0.28 molecule. The results obtained strongly support previous findings indicating the structural equivalence of inhibitor 0.28 with each inhibitor-0.19 protomer and the common phylogenetic origin of these protein alpha-amylase inhibitors from wheat kernel.
两种分子量为12000的小麦α-淀粉酶单体蛋白抑制剂，根据其凝胶电泳迁移率分别命名为抑制剂0.28和0.39。在不同pH值下以及存在或不存在解离剂和还原剂的情况下，它们在远紫外和近紫外区域的圆二色光谱几乎相同。两种抑制剂（0.28和0.39）都很容易因还原每个抑制剂分子中存在的五个二硫键而失活。这些特性与分子量为24000的小麦α-淀粉酶二聚体蛋白抑制剂（根据其凝胶电泳迁移率命名为抑制剂0.19）所表现出的特性非常相似。在不分离其亚基的情况下测定了0.19抑制剂的N端序列，并与Redman [(1976) Biochem. J. 155, 193--195]报道的0.28抑制剂的N端序列进行了比较。比较了还原和羧甲基化的抑制剂0.19和0.28经胰蛋白酶消化后的肽“图谱”。每个抑制剂0.19原体和抑制剂0.28分子共价结合一分子还原糖。所得结果有力地支持了先前的研究结果，表明抑制剂0.28与每个抑制剂0.19原体在结构上等同，以及这些来自小麦籽粒的α-淀粉酶蛋白抑制剂具有共同的系统发生起源。
