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41.
Yataro Obata Haruo Tanaka Yoshinori Ishikawa 《Bioscience, biotechnology, and biochemistry》2013,77(2):104-110
The recent findings1~3) that prenylmercaptan (3-methyl-2-butene-1-thiol) is the major component of the sunlight flavor of beer has led us to investigate the pathway of its evolution. S-Prenyl-l-cysteine, S-(3-methyl-2-butenyl)-l-cysteine, was synthesized according to the general outline of A. Stoll et al.4) from l-cyteine and prenylbromide, since it was considered as one of the precursors of the sunlight flavor of beer. S-Prenyl-l-cysteine was a colorless and odorless crystal, but this compound generated prenylmercaptan when the aqueous solution was exposed to sunlight. The addition of a small amount of riboflavin to the solution as a photosensitizer increased the mercaptan evolution. Prenylmercaptan formed by sunlight was isolated as its 2,4-dinitrophenyl derivative and identified by the comparison of melting point, chromatographic behavior and infrared spectrum with an authentic sample and by its elemental analysis. 相似文献
42.
Yoshitaka Kokusho Shigeaki Kato Haruo Machida Shinjiro Iwasaki 《Bioscience, biotechnology, and biochemistry》2013,77(9):2515-2524
An extracellular phospholipase D from Actinomadura sp. Strain No. 362 was purified about 430-fold from the culture filtrate. The purified enzyme preparation was judged to be homogeneous on polyacrylamide gel electrophoresis. The molecular weight and isoelectric point of the enzyme were estimated to be about 50,000—60,000 and 6.4, respectively. The enzyme was most active at pH 5.5 and 50°C in the presence of Triton X-100, but showed the highest activity at pH 7.0 and 60 — 70°C in its absence. The enzyme was stable up to 30°C at pH 7.2 and also stable in the pH range of 4.0 to 8.0 on 2 hr incubation at 25°C. With regard to substrate specificity, this enzyme hydrolysed lecithin best among the phospholipids tested. It was activated by Fe3 +, Al3+, Mn2 +, Ca2 +, diethyl ether, sodium deoxycholate and Triton X-100, but was inhibited by cetyl pyridinium chloride and dodecylsulfate. 相似文献
43.
Haruo Misono Kouji Sugihara Yumiko Kuwamoto Shinji Nagata Susumu Nagasaki 《Bioscience, biotechnology, and biochemistry》2013,77(6):1491-1498
Leucine dehydrogenase [EC 1.4.1.9] was purified to homogeneity from Corynebacterium pseudodiphtheriticum ICR 2210. The enzyme consisted of a single polypeptide with a molecular weight of about 34,000. Stepwise Edman degradation provided the N-terminal sequence of the first 24 amino acids, and carboxypeptidase Y digestion provided the C-terminal sequence of the last 2 amino acids. Although the enzyme catalyzed the reversible deamination of various branched-chain l-amino acids, l-valine was the best substrate for oxidative deamination at pH 10.9 and the saturated concentration. The enzyme, however, had higher reactivity for l-leucine, and the kcat/Km value for l-leucine was higher than that for l-valine. The enzyme required NAD+ as a natural coenzyme. The NAD+ analogs 3-acetylpyridine-NAD+ and deamino-NAD+ were much better coenzymes than NAD +. The enzyme activity was significantly reduced by sulfhydryl reagents and pyridoxal 5′-phosphate. d-Enantiomers of the substrate amino acids competitively inhibited the oxidation of l-valine. 相似文献
44.
45.
Takahide Saito Naomichi Iso Haruo Mizuno Hiroo Kanhda Yoshio Suyama Shirô Kawamura 《Bioscience, biotechnology, and biochemistry》2013,77(10):1941-1946
The mucin obtained from a natto sample was found to be composed of 58 % of γ-polyglutamic acid and 40% of polysaccharide. The ratio of l- and d-glutamic acid was determined to be 58:42 using l-glutamic acid decarboxylase. The weight- and z-average molecular weight were 2.08 × 105 and 2.22 × 105, respectively. The distribution curve of the sedimentation coefficient showed a small heterogeneity. The mucin molecule was considered to be randomly coiled at pH 5.0 ~ 8.8 and to be a rod-like molecule in the lower pH region. 相似文献
46.
The aqueous solutions of 2-alkyl-thiazolidine-4-carboxylic acids and mercaptals of l-cysteine were exposed to sunlight in the presence of a small amount of riboflavin. Hydrogen sulfide, ammonia, carbon dioxide and carbonyl compounds were the photolysis products.As for the carbonyl compounds, formaldehyde and acetaldehyde were identified from thiazolidine-4-carboxylic acid and djenkolic acid, acetaldehyde from 2-methyl-thiazolidine-4-carboxylic acid and l-cysteine-mercaptal of acetaldehyde, and acetaldehyde and n-butyraldehyde from 2-n-propyl-thiazolidine-4-carboxylic acid and l-cysteine-mercaptal of n-butyraldehyde. 相似文献
47.
Yasuhiko Asada Katsuyuki Tanizawa Yoshiyasu Kawabata Haruo Misono Kenji Soda 《Bioscience, biotechnology, and biochemistry》2013,77(6):1513-1514
Soybean 7S and 11S globulins were stored at relative humidities (RHs) of 11% and 96% at 50°C. The redispersibility of the proteins at RH 96% decreased in a short time. However, it did not decrease, when stored for 45 days at RH 11%. Gel filtration showed that the proteins polymerized during storage. The effects of urea, sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (2-ME) on the redispersibilities of the proteins at RH 96% showed that the hydrogen, hydrophobic and disulfide bonds participate in the polymerization of 7S globulin, and that the disulfide bond is strongly related to the polymerization of 11S globulin. Redispersibility was restored with 2-ME in both the 7S and 11S globulins and some of the proteins in the supernatant redispersed with 2-ME were observed to be similar to the native ones with respect to the gel filtration, electrophoretic behavior and circular dichroism spectrum. 相似文献
48.
Fusao Tomita Hirofumi Nakano Haruo Honda Takeo Suzuki 《Bioscience, biotechnology, and biochemistry》2013,77(11):2183-2188
The isolation of chloramphenicol resistant strains from Corynebacterium hydrocarboclastus KY 4339 (rough type) was examined to seek a good source of corynecins (analogs of chloramphenicol). Various mutants resistant to chloramphenicol were isolated in the range from 50 to 1000 µg/ml by adaptation or induced mutagenesis by N-methyl-N′-nitro-N-nitro-soguanidine. Productivities of mutants related apparently to the degree of resistance from 50 to 500 µg/ml. Highly resistant mutants capable of growing in the presence of 1000 µg of chloramphenicol per ml showed decreased productivity which might be related to their lower growth rate in the fermentation medium.Further attempts to derive resistant mutants to structural analogs of aromatic amino acids resulted in only a slight improvement of productivity, indicating that aromatic amino acids might play minor regulatory roles in corynecins synthesis.The increase in productivity of corynecins by the best strain was about 4.5 fold of the parental strain. 相似文献
49.
Hiroshi Kase Haruo Tanaka Kiyoshi Nakayama 《Bioscience, biotechnology, and biochemistry》2013,77(13):2089-2096
Fifteen strains of bacteria were treated with ultraviolet light or N-methyl-N′-nitro-N-nitrosoguanidine to derive auxotrophic mutants, which were screened for their ability to produce l-threonine. A number of auxotrophs were derived from each strain. Among them, those which produced a large amount of l-threonine were found in Aerobacter aerogenes, Serratia marcescens and Escherichia coli, the members of the family Enterobacteriaceae. Nutritional requirements of these threonine producers were proved to be methionine, lysine, or α, ε-diaminopimelic acid (DAP).In A. aerogenes and E. coli, double and triple auxotrophs were derived with futher mutational treatment. As a, rule, imposition of additional block led to the increase of l-threonine production. In E. coli, many triple auxotrophs (DAP?, Met?, He?) and their isoleucine revertants were screened for their ability to produce l-threonine. Enhancement of l-threonine production was achieved with these mutants.One of the isoleucine revertants, KY8280, was used to investigate some cultural conditions. As a result, l-threonine accumulation reached to a level of 13.8 mg/ml with the medium containing 7.5% fructose. 相似文献
50.
Haruo Seto Noboru Ōtake Hiroyuki Kawai Si-Qi Luo Fu-Gang Qian Sheng-Li Pan 《Bioscience, biotechnology, and biochemistry》2013,77(6):1607-1611
Sixteen triterpenoid glycosides, named S13 to S25, S37, S38 and S40, were isolated from the root of Bupleurum polyclonum Y. Li et S. L. Pan, and their structures were determined from NMR spectral analyses. Among them, S24, S37 and S38 were found to be new substances, their structures being established as 30-β-d-glucopyranosyl 30-hydroxysaikosaponin-b2, 2″-O-acetylsaikosaponin-b2 and 3″-O>-acetylsaikosaponin-b2, respectively. 相似文献