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T Imada R Takayanagi T Inagami 《Biochemical and biophysical research communications》1987,143(2):587-592
With the objective of identifying specific peptidase responsible for the processing of atrial natriuretic factor precursor pro-ANF to the circulating active form ANF (99-126), a fluorometric assay method was devised using synthetic fluorogenic substrate Boc-Ala-Gly-Pro-Arg-MCA(methylcoumarinamide) which contains the amino acid sequence immediately adjacent to the arginyl peptide bond which is cleaved in the natural processing of pro-ANF. A protease which selectively cleaves this bond and produces the natural circulating peptide was identified in the particulate fraction of rat atrial homogenate and was solubilized by 1.6 M KCl. It was partially purified by affinity chromatography heparin-agarose column and was shown to be a serine protease. Its reaction product with natural pro-ANF was identified as ANF (99-126) containing 28 amino acid residues. 相似文献
4.
Tolerance induced by grafting semi-allogeneic adult skin to larval Xenopus laevis: Possible involvement of specific suppressor cell activity 总被引:3,自引:0,他引:3
Toshihiro Nakamura Mitsugu Maéno Shin Tochinai Chiaki Katagiri 《Differentiation; research in biological diversity》1987,35(2):108-114
Major histocompatibility complex (MHC)-homozygous Xenopus laevis were rendered tolerant to semi-allogeneic antigens by grafting skins of adult frogs during larval stages (larvally induced tolerance), and this tolerant state was compared with the tolerance induced in early thymectomized frogs by the grafting of semi-allogeneic nonlymphoid thymuses (thymus-reconstituted tolerance). In contrast to a total inability of thymus-reconstituted frogs both to reject skins and to exhibit a mixed leukocyte reaction (MLR) against the semi-allogeneic donor, larvally induced tolerant frogs showed a strong MLR against leukocytes of the tolerizing skin donor (split tolerance). Breakdown of the tolerant state in thymus-reconstituted frogs were easily accomplished by inoculation with syngeneic splenocytes, but this breakdown was extremely difficult to achieve in frogs with larvally induced tolerance. The injection of splenocytes from larvally induced tolerant frogs into normal frogs significantly suppressed semi-allogeneic graft rejection in the latter group; no suppression was obtained when splenocytes from thymus-reconstituted frogs were used. In addition, in the thymectomized frogs, recovery of allograft rejection capacity against the pertinent semi-allogeneic antigens were suppressed by the injection of splenocytes from larvally induced tolerant frogs, with the degree of suppression depending on the splenocyte dose. These results indicate that the larvally induced tolerant state is maintained by specifically induced suppressor cells affecting the in vivo allograft response but not the MLR. 相似文献
5.
Carboxyl-terminal deletion analysis of the Streptococcus mutans glucosyltransferase-I enzyme 总被引:9,自引:0,他引:9
Sequential deletion of the carboxyl-terminal amino acids (including the six direct repeating units) of the glucosyltransferase-I (GTF-I) enzyme of Streptococcus mutans revealed differential effects on sucrase and GTF activities. Removal of all but one repeating unit resulted in a truncated enzyme with significant sucrase activity but no detectable GTF activity. These results are compatible with the presence of two functional domains in the enzyme. 相似文献
6.
Nobuo Kato Sumiko Mizuno Yukio Imada Masayuki Shimao Chikahiro Sakazawa 《Applied microbiology and biotechnology》1988,27(5-6):567-571
Summary Formaldehyde dismutase was greatly stabilized by immobilization in a urethane prepolymer (PU-6). The immobilized enzyme exhibited stochiometrical dismutation of formaldehyde to methanol and formate in several repeated reactions. Conversion of methanol to formate occurred in a reaction with an immobilized enzyme system consisting of alcohol oxidase, catalase and formaldehyde dismutase, and with an intact cell-mixture of Hansenula polymorpha and Pseudomonas putida. Furthermore, the stability of the cell-mixture during repeated reactions was greatly improved by the immobilization, the 600 mM methanol added periodically being converted to formate in a 75% yield in 12 h. The immobilized cellsystem was also effective for the conversion of several aliphatic alcohols, C1 to C4, to the corresponding acids. 相似文献
7.
N Yuasa T Taniguchi M Goda M Shibatani T Imada H Hihara 《National Institute of Animal Health quarterly》1983,23(3):75-77
An attempt was made to isolate chicken anemia agent (CAA) from chickens suffering from anemia in the field by using MDCC - MSB1 , which was an established cell line derived from Marek's disease lymphoma. When 99 chickens of 15 flocks were examined, CAA was isolated from 58 chickens of 12 flocks. The rate of CAA isolation with MDCC - MSB1 cells was almost the same as that determined by an in vivo method by chick inoculation. It was shown that CAA was more closely concerned with anemic diseases of chickens in the field than fowl adenoviruses. 相似文献
8.
The effects of chemicals such as metal ions and typical organic enzyme inhibitors on the activity of deglycosylated β-fructofuranosidases ( P -1 and P -2) from Aureobasidium were observed and compared with those of native enzymes. P -1 and P -2 enzymes became sensitive to metal ions, such as Fe2+ , Co2+ , Ni2+ and Al3+ , after deglycosylation. The enzymes were also inhibited by a sulphydryl reagent (monoiodoacetic acid), a peptide-hydrolysing reagent (hydroxylamine) and chelating reagents (sodium citrate, EDTA and sodium azide) after deglycosylation. The importance of deglycosylation for the determination of the true characteristics of the enzymes against chemicals is discussed. 相似文献
9.
High pressure conditions stimulate expression of chloramphenicol acetyltransferase regulated by the lac promoter in Escherichia coli 总被引:1,自引:0,他引:1
Chiaki Kato Takako Sato Maria Smorawinska Koki Horikoshi 《FEMS microbiology letters》1994,122(1-2):91-96
Abstract Recombinant plasmids with the chloramphenicol acetyltransferase (CAT) structural gene behind several kinds of promoters were tested for expression in Escherichia coli during growth at atmospheric pressure (0.1 MPa) and at high pressure (30 MPa). Expression of the CAT gene from the lac promoter was remarkably activated (approx. 78-fold) by high pressure in the absence of the inducer isopropyl-β-d-thiogalactopyranoside (IPTG). The stimulation of the CAT activity by the lac promoter at high pressure did not simply result from an increased plasmid copy number, because the CAT activities from the other promoters and β-lactamase activities were unaffected at high pressure. 相似文献
10.
Dr Sachio Hayashi Sinji Sasao Yoshiyuki Takasaki Kiyohisa Imada 《Journal of industrial microbiology & biotechnology》1994,13(2):103-105
Summary -Fructofuranosidase, which produces fructo-oligosaccharides (1-kestose and nystose) from sucrose, was purified fromAureobasidium and immobilized on DEAE-cellulose at especially high efficiency (95%). The enzymatic profiles of the immobilized enzyme were almost identical to those of the native form except that the stability was slightly improved. The immobilized enzyme was stable during long-term continuous reaction for up to 360 h. 相似文献