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101.
102.
103.
Showdomycin inhibited pig brain ( with pseudo first-order kinetics. The rate of inhibition by showdomycin was examined in the presence of 16 combinations of four ligands, i.e., Na+, K+, Mg2+ and ATP, and was found to depend on the ligands added. Combinations of ligands were divided into five groups in terms of the magnitude of the rate constant; in the order of decreasing rate constants these were: (1), (2) , , and none, (3) , and , (4) and , , , and ATP. The highest rate was obtained in the presence of Na+, Mg2+ and ATP. The apparent concentrations of Na+, Mg2+ and ATP for half-maximum stimulation of inhibition () were 3 mM, 0.13 mM and 4μM, respectively. The rate was unchanged upon further increase in Na+ concentration from 140 to 1000 mM. The rates of inhibition could be explained on the basis of the enzyme forms present, including E1, E2, ES, E1-P and E2-P, i.e., E2 has higher reactivity with showdomycin than E1, while E2-P has almost the same reactivity as E1-P. We conclude that the reaction of ( proceeds via at least four kinds of enzyme form (E1, E2, E1 · nucleotide and EP), which all have different conformations. 相似文献
104.
Yoshimitsu Ueno Kohsuke Hori Ryo Yamauchi Makoto Kiso Akira Hasegawa Koji Kato 《Carbohydrate research》1981,96(1):65-72
Laminarabiose, cellobiose, and gentiobiose were acetonated with 2,2-dimethoxy-propane under various conditions. Two isopropylidene acetals in which the reducing D-glucose residue had the furanoid form were obtained from laminarabiose, and two, in which the reducing D-glucose residue formed the acyclic dimethyl acetal, from cellobiose. Gentiobiose gave both types of isopropylidene compound. 相似文献
105.
Absence of pantothenic acid in gramicidin S synthetase 2 obtained from some mutants of Bacillus brevis 总被引:2,自引:0,他引:2
The pantothenic acid content of gramicidin S synthetase 2(GS 2) was estimated microbiologically with enzymes obtained from the wild strain and gramicidin S-lacking mutant strains of Bacillus brevis. Four mutant enzymes from BI-4, C-3, E-1, and E-2 lacked pantothenic acid. Other mutant enzymes from BII-3, BI-3, BI-9, and BI-2 contained the same amount of pantothenic acid as the wild-type enzyme. Pantothenic acid-lacking GS 2 belonged to group V of mutant enzymes, which could activate all amino acids related to gramicidin S; their complementary enzyme, gramicidin S synthetase 1(GS 1), lacked racemizing activity. To ascertain whether 4'-phosphopantetheine is involved in the formation of D-phenylalanyl-L-prolyl diketopiperazine (DKP) and gramicidin S, combinations were tested of intact GS 1 from the wild strain with various mutant GS 2 either containing or lacking pantothenic acid. Only the combinations of wild-type GS 1 with mutant GS 2 containing pantothenic acid could synthesize DKP. Combinations with pantothenic acid-lacking GS 2 also failed to elongate peptide chains. Pantothenic acid-lacking GS 2 could bind the four amino acids which constitute gramicidin S as acyladenylates and thioesters, but the binding abilities were lower than those of the wild-type enzyme and other mutant enzymes containing the pantothenic group. 相似文献
106.
107.
Makoto Higurashi Kumiko Iijima Norihiko Ishikawa Hiroki Hoshina Nobuo Watanabe 《Human genetics》1979,46(2):163-172
Summary In order to ascertain the frequency of chromosome aberrations among newborn infants in Japan, a chromosome survey of a large number of newborn infants is in progress. A consecutive series of 12,319 newborn babies, 6382 male and 5937 female, have been screened for clinical manifestations of autosomal aberrations and for sex chromatin and sex chromosome aberrations. Chromosome studies were carried out on 694 infants with suspected chromosome aberrations. The clinically abnormal infants were screened by conventional staining, and banding techniques have been used in the part of the study performed since 1974. Of the clincally abnormal infants, 25 had abnormal karyotypes, including two males with a 47,XXY complement, one female with a 45,X complement, three male infants with a 47,XYY complement, two with trisomy 13 syndrome, three with trisomy 18 (including one case of mosaicism), eleven with Down's syndrome (including one case of mosaicism), one with B5p partial trisomy, one with cri-du-chat syndrome, and one with Y/D translocation. The overall results are comparable to those of previous population cytogenetic studies only in the autosomal trisomies and sex chromosome abnormalities and in that the observed frequencies were comparable to those found in studies in Caucasians.To whom offprint requests should be sent 相似文献
108.
K. Hori 《Journal of insect physiology》1975,21(6):1271-1274
Pectinase was detected in the salivary gland of the larvae of Lygus disponsi. The pectinase activity per bug may increase gradually from the first instar larva to the adult. The salivary gland of the third instar larva contained substances indirectly promoting plant growth, i.e. the factor promoting the activity of 3-indoleacetic acid (IAA) or the factor inhibiting the activity of IAA-oxidase, whereas those of the fourth and 5th instar larvae seemed to contain, in addition, auxins which directly promote plant growth. Larvae of all instars had a significant promoting factor only in fraction III of the salivary gland solution. The larvae are as toxic as the adults to sugar beet plants. The presence of pectinase and plant growth-promoting factors in the salivary gland is compared among mirid bugs, and their significance is discussed. 相似文献
109.
Yutaka Suzuki Yoshiteru Harada Akinori Ueno Makoto Katori Haruya Okabe 《Prostaglandins & other lipid mediators》1986,32(3)
Filling of the gastric lumen of rats with 1.0 M NaCl solution (5 ml) for 10 min under urethane anesthesia caused an increase in the gastric fluid concentrations of prostaglandin (PG) E2, 13, 14-dihydro-15-keto-PGE2 and 6-keto-PGF1α as determined by radioimmunoassay. PGE2 was the major PG generated. The levels of PGE2 in the gastric fluid were increased dose-dependently after filling the lumen with 0.3, 0.5, 0.7 or 1.0 M NaCl solutions. The pH of the gastric fluid increased similarly after 0.5 to 1.0 M NaCl solutions. Indomethacin (10 mg/kg, i.p.) suppressed the PGE2 increase caused by 1.0 M NaCl solution, but did not prevent the increase of the pH of the gastric fluid induced by intragastric 1.0 M NaCl. Infusion of tetragastrin (62.5 μg/kg/hr, i.v., for 10 min) caused a marked increase of acid secretion without modifying intragastic concentration of PGE2. The acid secretion due to tetragastrin was completely inhibited after intragastric administration of 1.0 M NaCl solution, while indomethacin restored the tetragastrin-induced acid secretion, with prevention of a rise of intragastric PGE2 levels. These observations suggest that 1.0 M NaCl solutions suppress basal intragastric acid through a mechanism which is independent of prostaglandins. In contrast, the suppression of tetragastrin-induced acid secretion by intragastric 1.0 M NaCl solution appears to be mediated through a release of prostaglandins 相似文献
110.
Stabilization of quaternary structure and activity of bovine liver catalase through encapsulation in liposomes 总被引:1,自引:0,他引:1
Makoto Yoshimoto Hideyuki Sakamoto Noriko Yoshimoto Ryoichi Kuboi Katsumi Nakao 《Enzyme and microbial technology》2007,41(6-7):849-858
Bovine liver catalase was encapsulated in an aqueous phase of the phospholipid vesicle (liposome) to improve the stability of its tetrameric structure and activity. The catalase-containing liposomes (CALs) prepared were 30, 50 and 100 nm in mean diameters (CAL30, CAL50 and CAL100, respectively). The CAL100 included the types I, II and III based on the amounts of catalase encapsulated. The CAL30, CAL50 and CAL100-I contained one catalase molecule per liposome, and the CAL100-II and CAL100-III on average 5.2 and 17 molecules, respectively. The storage stability of catalase in either CAL system was significantly increased compared to that of free catalase at 4 °C in a buffer of pH 7.4. At 55 °C, free catalase was much more deactivated especially with decreasing its concentration predominantly due to enhanced dissociation of catalase into subunits while it was so done at excessively high enzyme concentration mainly due to enhanced formation of catalase intermolecular aggregates. Among the three types of CAL100, the CAL100-II showed the highest thermal stability, indicating that an excess amount of catalase in the CAL100-III was also disadvantageous to maintain an active form of the catalase even in liposome. In the CAL100-III, however, the stability of catalase was significantly improved compared to that of free catalase at the same concentration. The CAL thermal stability was little affected by the liposome size as observed in the CAL30, CAL50 and CAL100-I. An intrinsic tryptophan fluorescence of the catalase recovered from the CAL100-II thermally treated at 55 °C revealed that a partially denatured catalase molecule was stabilized through its hydrophobic interaction with liposome membrane. This interaction depressed not only dissociation of catalase into subunits but also formation of an inactive intermolecular aggregate between the catalase molecules in a liposome. Furthermore, either type of CAL100 showed a higher stability than free catalase in the successive decompositions of 10 mM H2O2 at 25 °C mainly because the H2O2 concentration was kept low inside liposomes due to the permeation barrier of the lipid membrane to H2O2. 相似文献