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21.
Rat plasma high-molecular-weight kininogen. A simple method for purification and its characterization 总被引:2,自引:0,他引:2
High-molecular-weight kininogen has been isolated from rat plasma in three steps in a relatively high yield. The purified preparation gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the absence and presence of 2-mercaptoethanol, and the apparent Mr was estimated as 100,000. On incubation with rat plasma kallikrein, rat high Mr kininogen yielded a kinin-free protein consisting of a heavy chain (Mr = 64,000) and a light chain (Mr = 46,000), liberating bradykinin. The kinin-free protein was S-alkylated, and its heavy and light chains were separated by a zinc-chelating Sepharose 6B column. The amino acid compositions of rat high Mr kininogen and its heavy and light chains were very similar to those of bovine high Mr kininogen and its heavy and fragment 1.2-light chains, respectively. A high histidine content in the light chain of rat high Mr kininogen indicated the presence of a histidine-rich region in this protein as in bovine high Mr kininogen, although this region was not cleaved by rat plasma kallikrein. Rat high Mr kininogen corrected to normal values the prolonged activated partial thromboplastin time of Brown-Norway Katholiek rat plasma known to be deficient in high Mr kininogen and of Fitzgerald trait plasma. The kinin-free protein had the same correcting activity as intact high Mr kininogen. Rat high Mr kininogen also accelerated approximately 10-fold the surface-dependent activation of rat factor XII and prekallikrein, which was mediated with kaolin, amylose sulfate, and sulfatide. These results indicate that rat high Mr kininogen is quite similar to human and bovine high Mr kininogens in terms of biochemical and functional properties. 相似文献
22.
A Hara T Kato H Sawada K Fukuyama W L Epstein 《Comparative biochemistry and physiology. B, Comparative biochemistry》1985,82(2):269-274
A particulate acid phosphatase (EC 3.1.3.2, orthophosphoric monoester phosphohydrolase (acid optimum)) was extracted in 1 M KCl, from 2-day rat epidermis. The enzyme has a Mr of 32,000, but two forms, F1 and F2 with pI values of 8.6 and 8.3, respectively, were identified while the pI values of other acid phosphatases soluble in sucrose and Triton X-100 were all acidic. F1 and F2 also differed from other epidermal acid phosphatases because they were (a) activated by Fe2+ and reducing agents, (b) showed immunological cross-reactivity with purple acid phosphatase of rat spleen and (c) dephosphorylated phosvitin and alpha-casein even though they had rather high Km values. 相似文献
23.
Yohei Hashimoto Hiroyuki Ishizone Midori Moriyasu Kazuko Kawanishi Atsushi Kato Masaru Ogura 《Phytochemistry》1984,23(8):1807-1808
Three oleanane triterpenes were isolated from the roots of Periandra dulcis,and identified as 3β-hydroxy-25-al-olean-18-en-30-oic acid (periandric acid I), 3β-hydroxy-25-al-olean-12-en-30-oic acid (periandric acid II) and 3-oxo-25-hydroxy-olean-12-en-30-oic acid. The former two compounds (periandric acids I and II) were identical with the aglycones obtained by hydrolysis of periandrin I and II, respectively and the latter one was a new triterpene. 相似文献
24.
Overlapping of the coding regions for alpha and gamma components of penicillin-binding protein 1 b in Escherichia coli 总被引:16,自引:0,他引:16
Summary The mode of biosynthesis of penicillin-binding protein(PBP)-1 b in Escherichia coli was investigated by use of the plasmid carrying the ponB(PBP-1 b) gene region. Analyses of the products synthesized in minicells and in vitro showed that PBP-1 b was synthesized as two molecular species corresponding to the and components of PBP-1 b. The coding regions for the and components were located within the ca. 3.7 kb MluI-HincII fragment and transcribed in the direction from the HincII to the MluI site. The capacity for producing the component was abolished by a deletion extending to the MluI site ca. 0.7 kb inward from the HincII end of the ca. 3.7 kb fragment; the remaining 3.0 kb region with the MluI site at both ends directed the production of the component alone. The production of the component was enough to correct all the known defects caused by a ponB mutation. In addition to these results, the analyses for cross-reacting materials produced in correspondence to the various deletions indicated that the coding regions for the and components overlapped and that the N-terminal portion was responsible for the difference between the two components. The distal region about 0.7 kb long inward from the MluI end of the MluI-HincII fragment was dispensable for producing the functional PBP-1 b, although the PBP-1 b produced was curtailed. By a larger distal deletion reaching almost to the middle of the MluI-HincII fragment, the polypeptide produced for PBP-1 b lost the ability to bind penicillin and still retained a low but significant activity for glycan synthesis. We suggest, therefore, that the polypeptide portion required for transglycosylase activity resides on the N-terminal half of PBP-1 b, followed by the middle portion necessary for penicillin-binding and the C-terminal part dispensable for the function of PBP-1 b. 相似文献
25.
The modulating influence of the fluidity of cell membrane on excision repair of DNA in UV-irradiated Escherichia coli 总被引:3,自引:0,他引:3
When the extent of liquid holding recovery (LHR) was measured as a function of the temperature at the time of liquid holding and the Arrhenius plot was made, two distinctive phases for the LHR were demonstrated in UV-irradiated RecA- derivative of E. coli ole28E1, which are unable to synthesize and degrade unsaturated fatty acids. The inflection temperatures were 17-18 degrees C, 23-24 degrees C and 28-30 degrees C for linoleate-, oleate- and elaidate-grown cells, respectively. These temperatures well corresponded to the phase transition temperatures of the cell membrane supplemented with the fatty acid. It is therefore concluded that at least a component involved in in vivo excision repair in E. coli is associated with cell membrane. 相似文献
26.
Dipeptidyl aminopeptidase, which hydrolyzes the 7-(Gly-Pro)-4-methylcoumarinamide, has been purified from the brains of 3 week-old rats. It was purified about 2,600-fold by column chromatography on CM-cellulose, hydroxyapatite and Gly-Pro AH-Sepharose. This enzyme hydrolyzed Lys-Ala-beta-naphthylamide well with an optimum pH of 5.5. It was inhibited by diisopropyl fluorophosphate, phenyl-methanesulfonyl fluoride, some cations, and puromycin, but was not inhibited by p-chloromercuribenzoate, N-ethylmaleimide, dithiothreitol, EDTA, iodoacetic acid, and bacitracin, indicating that rat brain dipeptidyl aminopeptidase is a serine protease. This enzyme showed a molecular weight of 220,000 by gel filtration and of 51,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The properties of purified rat brain dipeptidyl aminopeptidase were similar to those of bovine pituitary dipeptidyl peptidase II, but the molecular weight and substrate specificity of these enzymes were different. 相似文献
27.
M Kurono Y Hirachi Y Kato Y Toda N Takemasa S Kotani T Takahashi I Tadokoro 《Biken journal》1983,26(3):103-111
Intergenus cell fusion of prokaryotic bacteria was demonstrated for the first time; namely, fusion products doubly resistant to streptomycin and tetracycline were produced by polyethylene glycol treatment of a mixture of the streptomycin-resistant L-form of Pseudomonas aeruginosa and tetracycline-resistant L-form of Escherichia coli. 相似文献
28.
29.
Cyclic oxyphosphoranes as model intermediates during splicing and cleavage of RNA: ab initio molecular orbital calculations on the conformational analysis. 下载免费PDF全文
Ab initio molecular orbital calculations have been carried out on hydrated adducts of methyl ethylene phosphate as a model intermediate during cleavage of RNA. Upon rotating the apical methoxyl group two kinds of stable conformers and two kinds of rotational transition states are located, the most stable conformation being gs-G where the dihedral angle between the apical methyl group and the basal ring oxygen is calculated to be 76 degrees. In this gs-G conformation one of the lone pairs on the apical oxygen is oriented antiperiplanar to the basal ring ester bond. The torsional energy required to rotate the methyl group about the phosphorus-apical oxygen bond leading to ts-C conformation, where the methyl group is eclipsed with the ring oxygen, is calculated to be 5.2 kcal/mol. Judging from the published substrate's coordinates in the RNase environment, the expected pentacoordinate-intermediate/transition state during the cleavage of RNA appears to be, in fact, the most stable gs-G conformation. 相似文献
30.
Nucleotide sequence of the glutamine synthetase gene (glnA) and its upstream region from Bacillus cereus 总被引:8,自引:0,他引:8
We have determined the complete nucleotide sequence of a 2.4 kb chromosomal EcoT22I-NspV fragment, containing the Bacillus cereus glnA gene (structural gene of glutamine synthetase). The deduced amino acid sequence indicates that the glutamine synthetase subunit consists of 444 amino acid residues (50,063 Da). Comparisons are made with reported amino acid sequences of glutamine synthetases from other bacteria. Upstrem of glnA we found an open reading frame of 129 codons (ORF129) preceded by the consensus sequence for a typical promoter. Maxicell experiments showed two polypeptide bands, with molecular weights in good agreement with that of glutamine synthetase and that of ORF129, in addition to vector-coded protein. It is possible that the product of this open reading frame upstream of glnA has a regulatory role in glutamine synthetase expression. 相似文献