蛋白质的电子结构与活性关系——理论与计算方法

随着生物工程的发展,要求对蛋白质的电子结构与活性关系进行研究。而不加分割地对蛋白质作完整分子的量子化学计算,至今尚未见报导。其原因在于,未能找到合适的数值计算方法。本文报导了这方面的研究成果。假设一个蛋白质由N个氨基酸残基构成,其中有L对硫-硫键,每一个氨基酸残基有m_n个单元轨道,则整个蛋白质分子的分子轨道可以写成这些单元轨道的线性组合:     

Highly efficient detection of insulinotropic action of glucagon via GLP-1 receptor in mice pancreatic beta-cell with a novel perfusion microchip

Glucagon exhibits insulinotropic ability by activating cAMP through glucagon or glucagon-like peptide-1(GLP-1) receptors.To investigate the mechanism of endogenous and exogenous glucagon on insulin release,we studied the receptor selectivity on pancreatic islet beta-cells by switching the glucose concentration from 20 mmol/L to 0 mmol/L To measure the exact temporal relationship between glucagon and insulin release,we developed a quick,small volume,multi-channel polydimethylsiloxane(PDMS) microchip.At 0 mmol/L glucose,we observed an insulinotropic effect in both INS-1 cells and islets.Meanwhile,we observed a 63 ± 6.27 s delay of endogenous glucagon-induced insulin release.After treatment with glucagon and GLP-1 receptor antagonists,we found that endogenous glucagon utilized the glucagon receptor,whereas exogenous glucagon primarily utilized the GLP-1 receptor to promote insulin secretion.The microchip can also be used to describe the "glucagonocentric" vision of diabetes pathophysiology.Taken together,the insulinotropic mechanism of different receptors should be taken into account in clinical treatments.     

Accessing the Long‐Lived Triplet Excited States in Transition‐Metal Complexes: Molecular Design Rationales and Applications

Transition‐metal complex triplet photosensitizers are versatile compounds that have been widely used in photocatalysis, photovoltaics, photodynamic therapy (PDT) and triplet–triplet annihilation (TTA) upconversion. The principal photophysical processes in these applications are the intermolecular energy transfer or electron transfer. One of the major challenges facing these triplet photosensitizers is the short triplet‐state lifetime, which is detrimental to the above‐mentioned photophysical processes. In order to address this challenge, transition‐metal complexes showing long‐lived triplet excited states are highly desired. This review article summarizes the development of this fascinating area, including the molecular design rationales, the principal photophysical properties, and the applications of these complexes in PDT and TTA upconversion.

     

An improved interfacial coacervation technique to fabricate biodegradable nanocapsules of an aqueous peptide solution from polylactide and its block copolymers with poly(ethylene glycol)

ABA block copolymers of polylactide and poly(ethylene glycol) as amphiphilic bioabsorbable polymers were synthesized by the ring-opening polymerization of dl- lactide onto poly(ethylene glycol) (PEG 2000 or PEG 6000) and their structures were characterized on the basis of proton NMR. Biodegradable nanocapsules of an aqueous insulin solution were prepared from the block copolymers and polylactide by an improved interfacial coacervation technique. The results showed that the diameters of the nanocapsules were mainly dependent on the ratio of the two chains in the block polymers. The size of the nanocapsules decreased with an increase in the amount of surfactant used. More insulin solution resulted in an enlargement of the nanocapsules in diameter. In an optimum condition, biodegradable nanocapsules could be achieved with a size around 250 nm with a narrow distribution. The encapsulation percentages of insulin were larger in the nanocapsules from the PEG 2000 copolymers than in those from the PEG 6000 analogs and changed with the ratios of the blocks in the block copolymers. Received: 17 July 2000 Accepted: 24 November 2000     

金属钒化合物作为胰岛素模拟物的研究进展

综述了金属钒化合物作为胰岛素模拟物研究领域的背景,内容及潜在的应用和发展前景,详尽地介绍了有胰岛素样活性的金属钒化合物的类型及其作用机制等方面的研究进展。     

胰岛素与其受体分子相互作用的ESR的波谱研究

本文首次制备了胰岛素氮氧自由基,研究了胰岛素探针与其受体结合过程中ESR波谱参数的动力学变化.实验表明胰岛素与其受体结合前后,膜蛋白质的构象、胰岛素分子的旋转相关时间(τ_c)和胰岛素氮氧自由基的ESR波谱振幅(h₀)均发生明显的变化,这些变化均与胰岛素-受体的内噬现象有关系.当封闭受体上的巯基、氨基或羟基时,胰岛素与其受体的结合能力便受到一定的阻抑作用.