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Geoffrey R. Banks David G. Barker 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1985,826(4):180-185
Yeast DNA ligase is radioactively labelled in vitro by incubating a crude cell extract with [α-32P]ATP. The product of this reaction is the stable covalent ligase-AMP adduct, which can be characterized by its reactivity with either pyrophosphate or nicked DNA and visualized by gel electrophoresis and autoradiography. The Saccharomyces cerevisiae DNA ligase was identified as an 89 kDa polypeptide by exploiting the fact that transformants with multiple copies of the plasmid-encoded DNA ligase (CDC9) gene overproduce the enzyme by two orders of magnitude. A similar strategy has been used to identify the Schizosaccharomyces pombe DNA ligase as an 87 kDa polypeptide. Both values agree well with the coding capacities of the respective cloned gene sequences. When the S. cerevisiae ligase is greatly overproduced with respect to wild-type levels, a second polypeptide of 78.5 kDa is also labelled and has the same properties as the 89 kDa adduct. We suggest that this polypeptide is generated by proteolysis. 相似文献
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Internode length in Pisum. I. The effect of the Le/le gene difference on endogenous gibberellin-like substances 总被引:2,自引:0,他引:2
The allelopathic potential of the dry fruits of Washingtonia filifera (L. Linden) H. Wendl. was investigated. Leachates from fruits inhibited the germination of lettuce, wheat, red cabbage and cucumber seeds. The inhibitory effect was partly neutralized by kinetin (20 mg 1−1 ) and gibberellic acid (50 mg 1−1 ). The effect of kinetin was more pronounced at 25°C than at 20°C. Substances inhibiting germination were localized in the pericarp of the fruit and were resistant to high temperature. 相似文献
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Myoglobin (Mb) is the classic vertebrate oxygen-binding protein present in aerobic striated muscles. It functions principally in oxygen delivery and provides muscle with its characteristic red colour. Members of the Antarctic icefish family (Channichthyidae) are widely thought to be extraordinary for lacking cardiac Mb expression, a fact that has been attributed to their low metabolic rate and unusual evolutionary history. Here, we report that cardiac Mb deficit, associated with pale heart colour, has evolved repeatedly during teleost evolution. This trait affects both gill- and air-breathing species from temperate to tropical habitats across a full range of salinities. Cardiac Mb deficit results from total pseudogenization in three-spined stickleback and is associated with a massive reduction in mRNA level in two species that evidently retain functional Mb. The results suggest that near or complete absence of Mb-assisted oxygen delivery to heart muscle is a common facet of teleost biodiversity, even affecting lineages with notable oxygen demands. We suggest that Mb deficit may affect how different teleost species deal with increased tissue oxygen demands arising under climate change. 相似文献
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Ian H. Frasher Timothy Coolbear Sailen Mookerjea 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,799(2):102-105
Induction of inflammation by turpentine injection caused 1.5–2-fold increase of both sialy- and galactosyltransferase activity in liver homogenates. The effect was apparent after 12 h turpentine treatment. Serum sialytransferase activity started to increase in the inflamed rats after 18 h, reaching a maximum of 4-fold at 48 h. In contrast, galactosyltransferase activity in serum showed no significant increase. The coordinated and temporal increase of sialytransferase activity in liver and serum suggest involvement of a specific mechanism for the preferential release of this enzyme into serum. 相似文献
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