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121.
Hideaki Yamada Toru Nagasawa Haruyuki Ohkishi Bunsei Kawakami Yoshiki Tani 《Biochemical and biophysical research communications》1981,100(3):1104-1110
Synthesis of D-cysteine from 3-chloro-D-alanine and hydrogen sulfide is catalyzed by highly purified 3-chloro-D-alanine hydrogen chloride-lyase from . The synthetic reaction proceeds optimally at pH 8.5, as a function of enzyme concentration and incubation time. The enzymatically synthesized D-cysteine was isolated from the large scale reaction mixture and identified by physicochemical means. 相似文献
122.
The concentration of ACTH in extracts of rat anterior pituitary was measured by both radioimmunoassay and bioassay at different stages following adrenalectomy. Both types of ACTH activity decreased the day immediately following adrenalectomy but increased gradually afterwards. Immunological ACTH activity increased to 250% of the control value and biological ACTH activity increased to 490% of control value 3 weeks after adrenalectomy. The increase in biological ACTH activity occurred earlier, and the rate of increase was greater, than that of the immunological ACTH activity. The distributions of molecular weight forms of ACTH in extracts of anterior pituitary lobes was determined by gel filtration. Three molecular weight forms of immunoassayable ACTH were detected. Biological ACTH activity appeared in the 2nd and the 3rd peaks. A striking change was observed after adrenalectomy in the distribution of biologically active forms of ACTH. The ratio of biological ACTH activity to immunological ACTH activity in each peak changed at various stages after adrenalectomy. This indicated the heterogenous nature of the ACTH included in each peak. At 2 and again at 3 weeks, biological activity markedly increased until it exceeded the immunological ACTH activity in the 2nd peak. Dexamethasone had little influence on the elution profile of either immunoassayable and biologically active ACTH in gel filtration. Adrenalectomy may possibly have an effect on the intracellular posttranslational processing of ACTH precursors which leads to the development of biological ACTH activity. 相似文献
123.
Nucleotide sequence of 5S ribosomal RNA from Lingula anatina. A study on the molecular evolution of 5S ribosomal RNA from a living fossil 总被引:8,自引:0,他引:8
By chromatography on columns of DEAE-Sephadex A-50 and Sephadex G-100, and electrophoresis on polyacrylamide gel, 5S rRNA was purified from a low-molecular-weight RNA fraction extracted from the total tissues of Lingula anatina. Complete digests of the 5S rRNA with RNase T1 [EC 3.1.4.8] and pancreatic RNase [EC 3.1.4.22] were sequenced by conventional column chromatography procedures. The nucleotide sequence of this RNA was determined mainly by a chemical method for sequencing the RNA 3' end-labeled with 32P (1), with the complement of the oligonucleotide catalog obtained by the complete RNase digestions of the RNA. By comparing the sequences of several invertebrate, vertebrate, and Chlorella 5S rRNAs, a phylogenic tree of the rRNAs was constructed and the time of divergence of Lingula was estimated. 相似文献
124.
125.
Tetsuo Suami Shigeru Nishiyama Yasuhide Ishikawa Shinichi Katsura 《Carbohydrate research》1978,65(1):57-64
The aminocyclitol antibiotic neamine has been modified by changing the configuration of one or two hydroxyl groups of the aminocyclitol moiety to elucidate the relationship between configuration and antimicrobial activity. 5-Epi-, 6-epi-, and 5,6-diepineamine have been prepared and their antimicrobial activity has been determined against several micro-organisms. 相似文献
126.
Coumarin, a specific inhibitor of the biosynthesis of celluloseof higher plant cell walls, inhibited the cellulose formationof Acetobacter xylinum. The degree of inhibition reached 55%in the presence of 1 mM coumarin, which causes 70% inhibitionin the case of plant cellulose. (Received April 12, 1976; ) 相似文献
127.
A small amount of cytoplasmic ß-1,4-glucan, whichmight be involved in the synthesis of cellulose in the cellwall, was found in the homogenate prepared from the hypocotylsof seedlings of Phaseolus aureus. Upon hydrolysis by cellulaseof the 20,000?g pellet from the cytoplasmic fraction of segmentsincubated in a [14C]-glucose solution, [14C]-cellobiose wasproduced, with specific radioactivities 3 to 10 times greaterthan those of the cellobiose from cellulose in the cell wallat various incubation periods. The incoporation of radioactivityfrom [14C]-glucose into this cytoplasmic ß-1,4-glucanwas therefore faster than that into cellulose constituting thecell wall. Hence, it seemed that the former ß-1,4-glucancould be turned over. To examine whether the- cytoplasmic ß-1,4-glucanis carried by some subcellular components, cytoplasmic ß-1,4-glucanin the cell was fractionated by differential centrifugation,two enzyme activities being measured as the markers of subcellularcomponents. The distribution of ß-1,4-glucan was similarto that of UDPG-glucosyltransferase activity but not to thatof IDP-ase activity. The result suggests that the cytoplasmicß-1,4-glucan has some relation to plasma membranes. Coumarin, known as a specific inhibitor for the biosynthesisof cellulose in plant cells, was shown to inhibit the incorporationof radiocarbon from [14C]-glucose into cytoplasmic ß-1,4-glucanto the same extent as that into cellulose in the cell wall ofthe hypocotyls.
1 Present address: Department of Biological Science, TohokuUniversity, Kawauchi, Sendai 980, Japan. (Received May 31, 1976; ) 相似文献
128.
Tetsuo Suami Shigeru Nishiyama Yasuhide Ishikawa Shinichi Katsura 《Carbohydrate research》1976,52(1):187-196
The aminocyclitol antibiotic neamine has been chemically modified at the hydroxyl group on C-6 of the 2-deoxystreptamine moiety. The partially acetylated neamine derivatives, 6,3′,4′-tri-O-acetyl- (3) and 5,3′,4′-tri-O-acetyl-1,3,2′,6′-tetra-N-(ethoxycarbonyl)neamine (4), were prepared by random hydrolysis of the 5,6-O-ethoxyethylidene derivative (2), followed by chromatographic purification. Condensation of 4 and 2,3,5-tri-O-benzoyl-d-ribofuranosyl chloride led to 6-O-(β-d-ribofuranosyl)neamine (7). Analogous condensation of 4 with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide or 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide afforded the corresponding 6-O-(d-hexopyranosyl)neamines. 相似文献
129.
The female silkworm, Bombyx mori, rapidly accumulates two storage proteins, that are synthesized by the fat body, in the haemolymph during the feeding stage of the last-larval instar, and then sequesters them from the haemolymph into fat body during the larval-pupal transformation.The rapid synthesis and uptake of storage proteins by the fat body are shown to be induced by allatectomy in the early-penultimate larval instar. A juvenile hormone analogue, methoprene, is highly effective in inhibiting the allatectomy-induced synthesis, and, in a higher dosage, further blocks the uptake. Allatectomy in the late-penultimate larval instar shortly before moulting does not enhance the storage protein synthesis, but causes the uptake to occur two days earlier in the last-larval instar. Injection of 20-hydroxyecdysone is not stimulatory for synthesis of the proteins, but is effective to induce their uptake. Starvation during the early last-larval instar completely blocks the synthesis.From these results, it is suggested that storage protein synthesis is induced in the absence of juvenile hormone by some supplementary stimulus, possibly the supply of nutrient after feeding, and uptake is induced by ecdysteroids after a decline in the juvenile hormone level. 相似文献
130.