Peroxovanadate inhibits Ca2+ release from mitochondria

Mitochondria contain a specific Ca²⁺ release pathway which operates when oxidized mitochondrial pyridine nucleotides are hydrolyzed. NAD⁺ hydrolysis and therefore Ca²⁺ release is possible when some vicinal thiols are cross-linked. Here we report that the thiol oxidant peroxovanadate inhibits the specific Ca²⁺ release pathway. In mitochondria, peroxovanadate causes a complete loss of reduced glutathione, which is not accompanied by formation of glutathione disulfide, and a partial loss of protein thiols. In model reactions, peroxovanadate oxidizes reduced glutathione predominantly to the sulfonate derivative, but does not react with glutathione disulfide. When the vicinal thiols relevant for Ca²⁺ release are cross-linked, Ca²⁺ release is no longer inhibited by peroxovanadate. Conversely, pretreatment of mitochondria with peroxovanadate makes them insensitive to compounds promoting the disulfide state. These results suggest that peroxovanadate inhibits the prooxidant-induced Ca²⁺ release from mitochondria by (i) depleting mitochondria of reduced glutathione and (ii) oxidizing the vicinal thiols relevant for Ca²⁺ release to a state higher than disulfide, presumably the sulfonate state. The findings provide further insight into the regulation of Ca²⁺ release from intact mitochondria, and may be relevant for a better understanding of the action of peroxovanadate in cells, where the compound can be insulin mimetic. Received 28 March 2002; received after revision 8 May 2002; accepted 15 May 2002     

分光光度法同时测定锗,钛和钼多种组分

痕量锗、钛和钼与邻苯二酚紫（PV）和溴化十六烷基三甲胺（CTMAB）在酸性介质中发生高灵敏的显色反应，所产生的三元络合物的吸收光谱严重重叠。用最小二乘法—分光光度法成功地测定了模拟样的上述3种痕量组分。结果表明，最小二乘法是化学计量学中一种可适用于较为复杂的痕量组分同时分光光度测定的优良的计算方法。     

Identification of a disulfide bonded protein from cytoplasm ofBacillus subtilis

Conclusion In this study, P23 was found to be a disulfide-bonded cytoplasmic protein, abundant in late exponential phase and stationary phase cells, and was hardly detected in early exponential phase cells, the cells of sporulation process and spores. Therefore, synthesis of P23 was regulated by some specific factors or/and cellular environment. Conclusively, cytoplasm has a mechanism to catalyze the formation of disulfide bonds, which is consistent with Dermanet al. ’s conclusion from mutation experiment^[1].     

润滑油多功能添加剂的研制

本文简述了润滑油多功能添加剂二烷基二硫代磷酸盐（ＺＤＤＰ＋ＭｏＤＴＰ）合成工艺，作用机理，并对其主要技术指标进行测试。润滑性能模拟评定结果表明该剂极压抗展性能良好，是一种高档润滑油的添加剂     

石脑油裂解结焦规律及抑制研究

对石脑油的结焦规律和DMDS对石脑油裂解时结焦的抑制效果进行了研究.结果表明石脑油裂解时其结焦主要集中在投料开始阶段,随裂解运行时间的延长结焦速率明显减缓,并且裂解温度对石脑油裂解的结焦速率的影响非常显著.在石脑油中添加200μg·g-1DMDS,可使结焦速率降低20%以上.根据实验室研究结果,在工业裂解装置上进行了结焦抑制试验,效果非常理想.     

2,2’-二硫联二苯并噻唑的电化学合成

 以KI-NaI为间接电解质,丙酮为溶剂,首次用间接电氧化的方法对2-巯基苯并噻唑进行偶联,高产率地得到了2,2’-二硫联二苯并噻唑.     

大肠杆菌硫氧还蛋白thioredoxin基因的克隆及表达

以大肠杆菌XL1blue为模板，通过PCR技术扩增大肠杆菌硫氧还蛋白基因，并将目的基因分别连接到克隆载体pUC18和表达载体pTrcHisC上，构建重组质粒．重组质粒pTrcHisC-TRX在大肠杆菌中高效表达，最后利用固定化金属螫合亲和层析技术(IMAC)获得较纯的目的蛋白，为进一步研究硫氧还蛋白的功能及其应用提供了条件．     

Zn（Ⅱ）与巯基苯并噻唑的次磺酰胺衍生物配合物的合成

本文介绍了Ｚｎ（Ⅱ）与巯基苯并噻唑的次磺酰胺衍生物ＤＭ、ＣＺ的配合物的合成，并进行了ＩＲ、ＵＶ、元素分析等表征研究，指认所合成的化合物为［Ｚｎ（ＤＭ）ＣＬ＿２］（简称ＺＤＭ）、［Ｚｎ（ＣＺ）＿２ＣＬ＿２］（简称ＺＣＺ）。     

Assembly of MHC class I peptide complexes from the perspective of disulfide bond formation

Assembly of functional major histocompatibility complex (MHC) class I peptide complexes within the endoplasmic reticulum is critically important for the development of an adaptive immune response. The highly regulated loading of peptides onto MHC class I molecules is controlled by a multi-component chaperone system called the MHC class I peptide loading complex. The recent identification of the thioredoxin family member ERp57 as a component of the loading complex led to an interesting question: Why is there a thiol-disulfide oxidoreductase inside a complex dedicated to inserting peptides into a receptor binding site? Most recently, specific ERp57-mediated disulfide bond rearrangements have been identified inside the loading complex. What these biochemical events mean for the peptide loading process remains a matter of conjecture. While several important questions wait to be answered, this review intends to summarize our current view of the oxidative folding of MHC class I molecules and addresses the question of how the receptor ligand interaction might be regulated by thiol-based redox reactions.