Bode H P, Friebel C, Fuhrmann G F
Institut für Pharmackologie und Toxikologie, Philipps-Universität Marburg, F.R.G.
Biochim Biophys Acta. 1990 Feb 28;1022(2):163-70. doi: 10.1016/0005-2736(90)90110-a.
During incubation with vanadyl, Saccharomyces cerevisiae yeast cells were able to accumulate millimolar concentrations of this divalent cation within an intracellular compartment. The intracellular vanadyl ions were bound to low molecular weight substances. This was indicated by the isotropic nature of the electron paramagnetic resonance (EPR) spectra of the respective samples. Accumulation of intracellular vanadyl was dependent on presence of glucose during incubation. It could be inhibited by various di- and trivalent metal cations. Of these cations lanthanum displayed the strongest inhibitory action. If yeast cells were exposed to more than 50 microM vanadyl sulfate at a pH higher than 4.0, a potassium loss into the medium was detected. The magnitude of this potassium loss suggests a damage of the plasma membrane caused by vanadyl. Upon addition of vanadate to yeast cells surface-bound vanadyl was detectable after several minutes by EPR. This could be the consequence of extracellular reduction of vanadate to vanadyl. The reduction was followed by a slow accumulation of intracellular vanadium, which could be inhibited by lanthanum or phosphate. Therefore, permeation of vanadyl into the cells can be assumed as one mechanism of vanadium accumulation by yeast during incubation with vanadate.
在与氧钒孵育期间，酿酒酵母细胞能够在细胞内区室积累毫摩尔浓度的这种二价阳离子。细胞内的氧钒离子与低分子量物质结合。这由各个样品的电子顺磁共振（EPR）光谱的各向同性性质表明。细胞内氧钒的积累取决于孵育期间葡萄糖的存在。它可被各种二价和三价金属阳离子抑制。在这些阳离子中，镧表现出最强的抑制作用。如果酵母细胞在高于4.0的pH值下暴露于超过50 microM的硫酸氧钒，会检测到钾流失到培养基中。这种钾流失的程度表明氧钒对质膜造成了损伤。向酵母细胞中添加钒酸盐后，几分钟后通过EPR可检测到表面结合的氧钒。这可能是钒酸盐在细胞外还原为氧钒的结果。还原之后是细胞内钒的缓慢积累，这可被镧或磷酸盐抑制。因此，可以认为氧钒渗透到细胞中是酵母在与钒酸盐孵育期间积累钒的一种机制。
