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81.
采用一种组合5’-AMP亲和层析、离子交换层析、分子筛层析以及重结晶的方法,从经硫酸铵沉淀初步分离的四个兔骨骼肌酶组分中逐步分离和纯化出醛缩酶等五种医用酶。本方法提取的五种酶均具有高比活和高纯度。本方法提取成本低,操作简便,酶活回收率高,因此具有应用价值 相似文献
82.
为了更加真实地模拟细胞内环境,在人肌肌酸激酶(HCK)的去折叠环境中同时加入了大分子拥挤试剂(葡聚糖)和小分子渗透剂(蔗糖),采用酶活性、荧光发射谱和溶液浊度检测等方法研究肌酸激酶在含有蔗糖和葡聚糖的混合拥挤环境中的稳定性,结果表明在肌酸激酶盐酸胍变性过程中,蔗糖不仅抑制肌酸激酶酶活性的丧失,还稳定肌酸激酶的构象,而葡聚糖对肌酸激酶保护能力相对较弱.对于热变性过程,相同质量浓度的蔗糖和葡聚糖能同等程度地减缓肌酸激酶活性的丧失,并抑制聚沉的产生.在葡聚糖和蔗糖同时存在的情况下,两者的保护作用可以累加,并共同维持肌酸激酶的稳定性. 相似文献
83.
84.
Protein kinase C (PKC) is an important signaling molecule in the heart, but its targets remain unclear. Using a PKC substrate
antibody, we detected a 40-kDa phosphorylated cardiac protein that was subsequently identified by tandem mass spectroscopy
as muscle creatine kinase (M-CK) with phosphorylation at serine 128. The forward reaction using ATP to generate phosphocreatine
was reduced, while the reverse reaction using phosphocreatine to generate ATP was increased following dephosphorylation of
immunoprecipitated M-CK with protein phosphatase 2A (PP2A) or PP2C. Despite higher PKC levels in diabetic hearts, decreased
phosphorylation of M-CK was more prominent than the reduction in its expression. Changes in CK activity in diabetic hearts
were similar to those found following dephosphorylation of M-CK from control hearts. The decrease in phosphorylation may act
as a compensatory mechanism to maintain CK activity at an appropriate level for cytosolic ATP regeneration in the diabetic
heart.
Received 15 September 2008; received after revision 30 September 2008; accepted 13 October 2008 相似文献
85.
Yun Zhang Zhong-yan Liang Shao-yang Zhang Fang-fang Huang Wei Wu Yuan Gao Zuo-bing Chen 《浙江大学学报(自然科学英文版)》2008,9(11):871-878
Objective: To determine the effects of albumin administration on lung injury and apoptosis in traumatic/hemorrhagic shock (T/HS) rats. Methods: Studies were performed on an in vivo model of spontaneously breathing rats with induced T/HS; the rats were subjected to femur fracture, ischemia for 30 min, and reperfusion for 20 min with Ringer's lactate solution (RS) or 5% (w/v) albumin (ALB), and the left lower lobes of the lungs were resected. Results: Albumin administered during reperfusion markedly attenuated injury of the lung and decreased the concentration of lactic acid and the number of in situ TdT-mediated dUTP nick-end labelling (TUNEL)-positive cells. Moreover, immunohistochemistry performed 24 h after reperfusion revealed increases in the level of nuclear factor κB (NF-κB), and phosphorylated p38 mitogen-activated protein kinase (MAPK) in the albumin-untreated group was down-regulated by albumin treatment when compared with the sham rats. Conclusion: Resuscitation with albumin attenuates tissue injury and inhibits T/HS-induced apoptosis in the lung via the p38 MAPK signal transduction pathway that functions to stimulate the activation of NF-κB. 相似文献
86.
The epidermal growth factor family of receptor tyrosine kinases (ErbBs) plays essential roles in regulating cell proliferation, survival, differentiation and migration. The ErbB receptors carry out both redundant and restricted functions in mammalian development and in the maintenance of tissues in the adult mammal. Loss of regulation of the ErbB receptors underlies many human diseases, most notably cancer. Our understanding of the function and complex regulation of these receptors has fueled the development of targeted therapeutic agents for human malignancies in the last 15 years. Here we review the biology of ErbB receptors, including their structure, signaling, regulation, and roles in development and disease, then briefly touch on their increasing roles as targets for cancer therapy. 相似文献
87.
王芳斌 《湖南文理学院学报(自然科学版)》1999,(3)
阐述以葡萄糖酸钙、浓硫酸、氧化锌为主要原料合成葡萄糖酸锌的新方法。详细研究了反应时间、反应温度、结晶条件、结晶时间等因素的影响,并对最终产物进行了元素分析和红外光谱分析。 相似文献
88.
ZHANG Yuqiu 《自然科学进展(英文版)》2006,16(4):338-345
The pain experience includes a sensory-discriminative and an emotional-affective components. The affective dimension refers to the unpleasantness or aversion of sensation. The great progress at the genetic, molecular, cellular, and systemic levels on the study of the sensory dimension of pain has been made over past four decades. However, “to consider only the sensory features of pain, and ignore its motivational and affective properties, is to look at only part of the problem and not even the most important part of that”. A line of clinic observations indicate that the patients with chronic pain suffer from much more affective disturbance than pain itself. Obviously, physiological arousal and hypervigilance to pain cause negative affect, such as anxiety, anger, worry, aversion, even tendency of suicide, these negative affective states in turn enhance pain sensation. Today, more and more attention has been paid to the study on mechanisms underlying affective dimension of pain. In order to deepen and expand our understanding of the nature of pain, this review summarizes the main progress and recent findings from our laboratory regarding affective component of pain in neuroanatomy, neurophysiology, and cell biochemistry. 相似文献
89.
CD100 is a leukocyte semaphorin 总被引:5,自引:0,他引:5
S. Delaire A. Elhabazi A. Bensussan L. Boumsell 《Cellular and molecular life sciences : CMLS》1998,54(11):1265-1276
CD100 was originally described as an activation molecule on the surface of human T lymphocytes. Its triggering through distinct
epitopes leads to different signals of costimulation with phorbol myristate acetate (PMA) or with CD3 and CD2. Interestingly,
CD100 was shown to associate with different partner molecules in T cells. First, CD100 can associate with CD45, a key molecule
with protein tyrosine phosphatase activity involved in T-cell transduction this association is physical and has functional
consequences for both partners. Second, CD100 interacts in its cytoplasmic domain with a Ser/Thr kinase for which it represents
a preferential substrate. Recently, CD100 was identified as a member of the semaphorin gene family. This family comprises
approximately 20 structurally related proteins. The first semaphorins were identified in the developing nervous system. Function
has been shown for only some of them and involves repulsion during growth cone guidance. Since CD100 was the first semaphorin
identified in the immune system, this raises the possibility of the involvement of members of the semaphorin family in other
physiological phenomena outside the nervous system.
Received 1 March 1998; received after revision 8 June 1998; accepted 8 June 1998 相似文献
90.
简述了植物细胞的钙离子调控过程,对钙调蛋白、钙调磷酸酶B类蛋白和钙离子依赖型蛋白质激酶3类钙靶蛋白的最新研究进展进行了综述。 相似文献