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Z Z Chen G P Schwartz L Zong G T Burke J D Chanley P G Katsoyannis 《Biochemistry》1988,27(16):6105-6111
A two-chain, disulfide linked, insulin-like compound embodying the A-domain of insulin-like growth factor I (IGF-I) and the B-chain of insulin has been synthesized and characterized with respect to insulin-like biological activity and growth-promoting potency. The compound displays a potency of ca. 41% relative to insulin in assays for insulin-like activity (e.g., lipogenesis) but significantly higher activity than insulin, ca. 730% relative to insulin, in growth factor assays (e.g., thymidine incorporation). The compound is, however, a less potent growth factor than IGF-I itself, ca. 26.5% relative to IGF-I, and is not recognized by IGF carrier proteins. We conclude that structural features contained in the A-domain of IGF-I are primarily responsible for the growth-promoting ability displayed by IGF-I, while features in the B-domain are responsible for recognition by IGF carrier proteins. 相似文献
3.
中国的脊棱齿象属(Stegolophodon)化石 总被引:6,自引:2,他引:4
剑齿象属 Stegodon 起源于脊棱齿象属 Stegolophodon,两者都是亚洲大陆晚新生代的特有动物,本文讨论两属中一些种的性质和分类位置问题,并记述了药铺脊棱齿象 Stegolophodon officinalis 的新材料. 相似文献
4.
Min-Hua Zong Toshiaku Fukui Takuo Kawamoto Atsuo Tanaka 《Applied microbiology and biotechnology》1991,36(1):40-43
Summary Bioconversion of three organosilicon compounds of different chain length between the silicon atom and the hydroxyl group (Me3Si(CH2)nOH, n = 1–3) by horse liver alcohol dehydrogenase (HLADH, EC 1.1.1.1.) was studied. Furthermore, the effect of the silicon atom on the HLADH-catalysed reaction was examined in comparison with the corresponding carbon compounds. HLADH could catalyse the dehydrogenation of trimethylsilyeethanol (n = 2) and trimethylsilylpropanol (n = 3). Trimethylsilylethanol was a better substrate than both its carbon analogue, 3,3-dimethylbutanol, and ethanol. The improved activity of HLADH on trimethylsilylethanol could be accounted for by a higher affinity toward HLADH and a lower activation energy of the reaction by HLADH than those of the carbon counterpart. These are derived from physical properties of the silicon atom, that is, the lower electronegativity and the bigger radius than those of the carbon atom. In contrast, HLADH showed no activity on trimethylsilylmethanol (n = 1), whereas it catalysed the dehydrogenation of the carbon analogue, 2,2-dimethylpropanol, fairly well. The reason for the inactivity of HLADH in the case of trimethylsilylmethanol based on the electric effect of the silicon atom is also discussed.
Offsprint requests to: A. Tanaka 相似文献
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肾综合征出血热(HFRS)为一组抗原性密切相关的布尼亚科汉坦病毒引起的急性传染病。在我国存在至少两种临床表现、动物宿主及流行特征截然不同的血清型别,即血清Ⅰ型(汉坦型)和血清Ⅱ型(汉城型)。这两型病毒间的血清学定型已有报道。近年来,除啮齿类动物外,从临床病人以及非啮齿类动物体内也分离到了HFRS病毒。同时出现两类型别毒株共存,以及从家鼠体内分离到野鼠型毒株或从野鼠体内分离到家鼠型毒株的复杂情形。为此,准确检定并鉴别不同来源毒株型别,将为深入了解其病原学、流行病学以及制定疫苗生产策略提供重要信息。 相似文献
7.
生物复苏——大绝灭后生物演化历史的第一幕 总被引:12,自引:1,他引:11
生命史是一部生物界短期,快速剧变与长期,慢速稳定相互交替的历史。大绝灭(即集群绝灭)事件反映了全球环境的大突变,点断了地质历史中的生命记录及其发展历程,预示着生物界的演化出现了最有意义的飞跃,近年来尝试研究大绝灭后全球生物界的残存-复苏及其基本型式,并探索复苏的控制因素,标志着地质科学中一个重心的转移(即从大绝灭转向其后的生物残存与复苏的研究)。生物复苏揭示了大绝灭后生物演化历史的第一幕,其研究的 相似文献
8.
二核苷酸重复多态性的非同位素检测及其在基因诊断中的应用 总被引:9,自引:1,他引:8
本文报道了一种检测二核苷酸重复多态性的简便的非同位素法,利用重复序列两侧的特异引物进行PCR扩增,产生的等位片段在薄层变性聚丙烯酰胺凝胶电泳上分离,再用灵敏的银染法显色。该方法不需要标记PCR产物,简便、快速,分辨率可达1bp,并可用多对引物同时进行多重PCR分析。用此方法对DMD家系成员dystrophin基因的5'-脑型外显子止游区和3'-非翻译区的两个(CA)。位点进行了扩增片段长度多态性分 相似文献
9.
Distinctive effects of the carboxyl-terminal sequence of the insulin-like growth factor I receptor on its signaling functions. 总被引:2,自引:1,他引:1 下载免费PDF全文
We have shown previously that the extracellular sequences of the human insulin receptor (IR) and the insulin-like growth factor I receptor (IGFR) have an inhibitory effect on protein tyrosine kinase (PTK) activity and on the biological functions of their respective Gag-receptor fusion proteins. To study the role of IGFR carboxyl sequence in modulation of the Gag-IGFR PTK and biological activities, five mutants, CM1, CM2, CM3, CM4, and CM5, containing carboxyl deletions of 17, 27, 47, 67, and 88 amino acids (aa), respectively, were constructed from the parental virus UIGFR encoding the Gag-IGFR. Deletion of up to 27 aa had little effect on the cell-transforming and PTK activities of UIGFR. Deletions of 47 aa in CM3 abolished PTK and transforming activities. Surprisingly, a further deletion of 20 aa in CM4 beyond that in CM3 reactivated the kinase and transforming activities. CM5, containing a deletion of 20 aa beyond that in CM4, had only marginal transforming and PTK activities. We conclude that deletion of the carboxyl region of the Gag-IGFR inactivates, instead of activating as in the case with Gag-IR, its transforming activity and the amino acid sequence 1250 to 1310 is essential for PTK and transforming activities. Analysis of the ability of the full-length IGFR and its mutant receptors described above to associate with phosphatidylinositol 3 kinase indicated that the association required PTK activity and tyrosine phosphorylation of the receptors and correlated well with their transforming activities. The carboxyl 88 aa are not essential for the association. 相似文献
10.
泥河湾盆地发现短喙象化石 总被引:1,自引:1,他引:0
本文记述泥河湾盆地河北蔚县两个地点发现的化石,它们被鉴定为短喙象类的?Anancus和Pentalopodon两个属。 相似文献