Serra M A, Sabbioni E, Marchesini A, Pintar A, Valoti M
Radiochemistry Division, Joint Research Centre, Ispra, Italy.
Biol Trace Elem Res. 1989;23:151-64. doi: 10.1007/BF02917186.
Vanadate ions are shown to inhibit horseradish, squash, and rat intestinal peroxidases by following the reaction spectrophotometrically in a wide range of vanadate concentrations. I50 in phosphate buffer were 43, 9.4, and 535 microM, respectively. No inhibitory effect was found on cow milk lactoperoxidase and beef liver catalase. Gel filtration of peroxidases in the presence of vanadate, as carried out by radioactive 48V for horseradish peroxidases (either in aerobic or anoxic conditions) and neutron activation analysis (NAA) for squash peroxidase, demonstrated a binding of vanadium to these enzymes in stoichiometric amounts. Electron paramagnetic resonance spectra of the eluted peaks for the former peroxidase indicated that vanadium is in the +5 oxidation state, but an equilibrium between V (V) and V (IV) in the assay conditions cannot be discarded. Although the inhibitory mechanism remains obscure, some hypotheses are considered. The potential implications that the inhibitory effect of vanadium might have on plant and animal metabolism are also discussed.
通过在广泛的钒酸盐浓度范围内用分光光度法跟踪反应，结果表明钒酸盐离子可抑制辣根、南瓜和大鼠肠道过氧化物酶。在磷酸盐缓冲液中的半数抑制浓度（I50）分别为43、9.4和535微摩尔。未发现对牛乳过氧化物酶和牛肝过氧化氢酶有抑制作用。在钒酸盐存在的情况下，通过对辣根过氧化物酶（在有氧或无氧条件下）进行放射性48V凝胶过滤以及对南瓜过氧化物酶进行中子活化分析（NAA），结果表明钒以化学计量的量与这些酶结合。前一种过氧化物酶洗脱峰的电子顺磁共振光谱表明钒处于+5氧化态，但在测定条件下V（V）和V（IV）之间的平衡也不能排除。尽管抑制机制仍不清楚，但也考虑了一些假设。还讨论了钒的抑制作用可能对植物和动物代谢产生的潜在影响。
