McCormick L D
Biophys J. 1985 Mar;47(3):381-5. doi: 10.1016/S0006-3495(85)83929-1.
Particle-induced x-ray emission (PIXE) was used to determine the trace element content of bovine retinal disk membranes. PIXE is a multielemental analytical technique capable of the simultaneous detection and quantization of all elements from sodium and above in atomic number. The multielemental capability of PIXE allows the analysis time per element to be very low if a number of elements are detected in each sample. In addition, the multielemental capability of PIXE can be used to determine elemental content with respect to an internal reference. Here the content of detected trace element per rhodopsin was determined without recourse to an external rhodopsin assay. This was accomplished by using the sulfur content of rhodopsin as an internal reference. Detected trace element contents per rhodopsin were 1.58 +/- 0.049 Ca, 0.081 +/- 0.024 Fe, 0.393 +/- 0.200 Cu, and 0.150 +/- 0.031 Zn. Upper limits were placed on the amount of manganese, molybdenum, and nickel per rhodopsin as 0.019, 0.019, and 0.006, respectively. Two proteins known to be present in disk membranes, retinol dehydrogenase and a large protein, approximately 238,000 mol wt, are considered as potential metallo-proteins. No correlation was observed between the content of any detected element and bleaching levels.
粒子诱导X射线发射（PIXE）技术被用于测定牛视网膜盘膜中的微量元素含量。PIXE是一种多元素分析技术，能够同时检测和量化原子序数从钠及以上的所有元素。如果在每个样品中检测到多种元素，PIXE的多元素分析能力可使每个元素的分析时间非常短。此外，PIXE的多元素分析能力可用于相对于内标物来测定元素含量。在此，无需借助外部视紫红质测定法，就能测定每个视紫红质中检测到的微量元素含量。这是通过将视紫红质中的硫含量用作内标物来实现的。每个视紫红质中检测到的微量元素含量分别为：钙1.58±0.049、铁0.081±0.024、铜0.393±0.200和锌0.150±0.031。每个视紫红质中锰、钼和镍的含量上限分别为0.019、0.019和0.006。已知存在于盘膜中的两种蛋白质，即视黄醇脱氢酶和一种大约238,000分子量的大蛋白质，被认为是潜在的金属蛋白。未观察到任何检测元素的含量与漂白水平之间存在相关性。
