http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Pseudomonas sp. CB-33이 생산하는 β-Xylosidase의 특성
유진환,김현구,김치경,임재윤 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.2
Pseudomonas sp. CB-33 균주의 배양 상등액으로부터 ammonium sulfate 침전법, PEI 침전법, DEAE-Sephadex column chromatography, gel column chromatography 그리고 preparative disc gel electrophoresis를 이용하여 β-xylosidase를 정제하였다. 정제된 효소의 Km 값은 4.6 mM이었다. 효소활성의 최적 pH는 7.0이었으며 pH 6.5~9 범위에서 안정하였다. 최적 활성온도는 45℃였으며, 각 온도에서 30분 동안 정치하였을 때 35℃까지 안정하였다. SDS-PAGE에 의해 효소의 분자량을 측정해 본 결과 약 44,000dalton이었다. HG^2+, Cu^2+ 그리고 Zn^2+는 효소활성을 저해하였고, 여러 화학변형제로 효소에 처리해 본 결과 tyrosine과 tryptophan이 효소활성에 관여하고 있을 것으로 추정된다. 여러가지 기질에 대한 특이성을 조사해 본 결과 pNPX 뿐만 아니라 pNPA도 분해하였다. Xylan에 endoxylanase만을 작용시켰을 때보다 β-xylosidase와 endoxylanase를 혼합작용 시켰을 때 xylan의 가수분해도는 약 2배 정도 증가하였다. 그리고 Pseudomonas sp. CB-33 균주가 생산하는 xylan 분해효소는 oat spelt xylan보다 birchwood xylan에 보다 효과적으로 작용하였다. The β-xylosidase was purified 99-fold from the culture supernatant of Pseudomonas sp. CB-33 by ammonium sulfate precipitation, PEI precipitation, DEAE-Sephadex column chromatography, Sephadex G-75 gel filtration chromatography and preparative disc gel electrophoresis. Molecular weight of the enzyme was estimated to be 44,000 by SDS polyacrylamide gel electrophoresis. The enzyme has a pH optimum for activity at 7.0 and is stable over pH 6.5~9.0. The optimal temperature of the enzyme was 45℃, and it enzymatic activity was completely inactivated at 55℃ for 30 min. Km value of the enzyme for p-nitrophenyl- β-D-xylopyranoside was calculated to be 4.6 mM. The effect of various reagents on the β-xylosidase activity was investigated. The enzyme activity was completely inhibited by Hg^2+, Cu^2+, and Zn^2+. The β-xylosidase was inactivated by tryptophan-specific reagent, N-bromosuccinimide and the enzyme was competitively inhibited by xylose. The β-xylosidase and endoxylanase from Pseudomonas sp. CB-33 hydrolized xylan synergically. The purified enzyme also showed α-L-arabinofuranosidase activity.
이상하,최재석,이광열,장영수,임인수,허우명,김재구,김범철 강원대학교 부속 환경연구소 2005 Journal of the Environment Vol.2 No.-
To investigate nutrient dynamics of the lake and fish community, both water and fish samples were collected at three different areas (dam site, upper inflowing and downstream of lake outfow) for one year from Sep.2004 to Aug.2005 During the experimental periods, mean concentration of chl, a in epilimnetic layer (0-5m) was 18.5mg^(-3) and transparency ranged from 0.3m to 2.4m, respectively. In nutrient, mean concentrations of TP and TN were 111 mgP m^(-3) and 4.4 mgN L^(-1), respectively. Based on the water quality standard suggested by U.S.EPA(*1976), the trophic state of Lake Doam was classified as eutrophic state. Total number of fish collected in Lake Doam was 9,600 indiveduals in 26 species of 6 family. Sixteen of Korean endemic soecies including H. mylodon, A. signifer, P. tenuicorpa occurred. O. mykiss as introduced fish was also found in Lake Doam. Dominant and subdominant species were P. herzi and Z. platypus that took about 34.6% and 22.5% of total fish composition, respectively. Six species including A. signifer. P. tenuicorpa. and R. kumgangensis were rare in Lake Doam. Pelagic typw of figh commonly occurred at upper regions, whereas benthic type was mainly domenated at downstream area. Therefore, pollution source inflowed from the upper regions did not seriously affect downstream area (Songcheon water system) due to the role of dam as pollutant barrier. In addition high appearance of Comat type of fish that si hybrid between gold fish (C.auratus) and C. auratus was found in the lake, It was unclear the reasons that high prorortion of mutant species apperared in the lake. Further more researches are required in this area.