Knüttel K, Müller A, Rehder D, Vilter H, Wittneben V
Faculty of Inorganic Chemistry, University of Bielefeld, Germany.
FEBS Lett. 1992 May 4;302(1):11-4. doi: 10.1016/0014-5793(92)80272-i.
Vanadate-dependent peroxidase A.n.I, the main isoenzyme (M(r) = 100 kDa) from the seaweed, Ascophyllum nodosum, contains 2 V per enzyme molecule (as shown by ICP-MS metal analysis) after complete reconstitution with vanadate (V), possibly distributed in a 1:1 ratio between the surface and active site. VO2+ is only weakly associated to the surface of A.n.I. There is no transport channel for VO2+. The EPR spectrum of the reduced holoenzyme is anisotropic (axial) already at room temperature, with EPR parameters similar to those of VO2+ complexes of small model peptides such as Ala-His, Gly-Tyr, Gly-Ser, Gly-Glu, Ser-Gly and Phe-Glu. The complex formation between Ala-His and H2VO4- in water has also been investigated (by 51V NMR); the formation constant at pH 7.2 amounts to 266(28) M-1.
依赖钒酸盐的过氧化物酶A.n.I是来自海藻泡叶藻的主要同工酶（分子量 = 100 kDa），在用钒酸盐（V）完全重构后，每个酶分子含有2个V（通过电感耦合等离子体质谱金属分析显示），可能以1:1的比例分布在表面和活性位点之间。VO2+仅与A.n.I的表面弱结合。不存在VO2+的运输通道。还原型全酶的电子顺磁共振谱在室温下就已经是各向异性的（轴向），其电子顺磁共振参数与小模型肽如丙氨酸 - 组氨酸、甘氨酸 - 酪氨酸、甘氨酸 - 丝氨酸、甘氨酸 - 谷氨酸、丝氨酸 - 甘氨酸和苯丙氨酸 - 谷氨酸的VO2+配合物相似。还研究了水中丙氨酸 - 组氨酸与H2VO4-之间的配合物形成（通过51V核磁共振）；在pH 7.2时的形成常数为266(28) M-1。
