• Title/Summary/Keyword: proteinase K

Search Result 321, Processing Time 0.084 seconds

The Proteinase Distributed in the Intestinal Organs of Fish 1. Purification of the Three Alkaline Proteinases from the Pyloric Caeca of Mackerel, Scomber japonicus (어류의 장기조직에 분포하는 단백질분해효소에 관한 연구 1. 고등어 유문수조직으로부터 3종의 알칼리성 단백질분해효소의 분리${\cdot}$정제)

  • PYEUN Jae-Hyeung;KIM Hyeung-Rak
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.19 no.6
    • /
    • pp.537-546
    • /
    • 1986
  • In the previous paper(Kim et al, 1986), the alkaline proteinase from the pyloric caeca of mackerel was shown relatively strong activity in the alkaline pH range. Therefore purification of the enzyme has been undertaken to identify the proteolytic enzyme and three alkaline proteinases were isolated by ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration. One percent sodium chloride solution was the most effective for the extraction of alkaline proteinase from the pyloric caeca of mackerel. Three alkaline proteinases temporarily designated Enz. A, B and C were isolated from the pyloric caeca of mackerel, and identified to be homogeneous with electrophoresis. The specific activity of the purified Enz. A, B and C was increased to 34, 53 and 37-fold over the crude enzyme solution, respectively. Yield of them was 1.6, 2.1 and $1.5\%$, respectively, and a combined yield was $5.2\%$.

  • PDF

Casein Phosphopeptide (CPP)-Producing Activity and Proteolytic Ability by Some Lactic Acid Bacteria (유산균의 Casein Phosphopeptide(CPP) 생산 및 단백질 분해 활성)

  • Cho, Yoon-Hee;Oh, Se-Jong
    • Food Science of Animal Resources
    • /
    • v.30 no.3
    • /
    • pp.443-448
    • /
    • 2010
  • Casein phosphopeptide (CPP) enhances calcium absorption in humans. Lactic acid bacteria (LAB) are capable of synthesis of cell-surface proteinase, which can hydrolyze milk protein and release several types of peptides in the medium. This study was conducted to characterize proteinase of LAB and to evaluate the CPP production from bovine milk. The content of CPP of milk produced by cell-free extract of LAB was determined based on the quantity of decomposed peptide from casein using the O-phthaldialdehyde (OPA) method. The proteolytic activity of LAB was assayed using fluorescein isothiocyanate (FITC)-labeled casein. Casein appeared to be a better substrate than whey proteins for extracellular proteinases of LAB. During fermentation, milk proteins were hydrolyzed by extracellular proteinase of LAB, resulting in an increase in the amount of free $NH_3$ groups. Overall, the results presented here indicate that CPP produced by LAB may be a promising material for novel applications in the dairy industry.

Comparative Quantification of LacZ (β-galactosidase) Gene from a Pure Cultured Escherichia coli K-12

  • Han, Ji-Sun;Kim, Chang-Gyun
    • Environmental Engineering Research
    • /
    • v.14 no.1
    • /
    • pp.63-67
    • /
    • 2009
  • Escherichia coli K-12 (E. coli K-12) is a representative indicator globally used for distinguishing and monitoring dynamic fates of pathogenic microorganisms in the environment. This study investigated how to most critically quantify lacZ ($\beta$-galactosidase) gene in E. coli K-12 by two different real-time polymerase chain reaction (real-time PCR) in association with three different DNA extraction practices. Three DNA extractions, i.e., sodium dodecyl sulfate (SDS)/proteinase K, magnetic beads and guanidium thiocyanate (GTC)/silica matrix were each compared for extracting total genomic DNA from E. coli K-12. Among them, GTC/silica matrix and magnetic beads beating similarly worked out to have the highest (22-23 ng/${\mu}L$) concentration of DNA extracted, but employing SDS/proteinase K had the lowest (10 ng/${\mu}L$) concentration of DNA retrieved. There were no significant differences in the quantification of the copy numbers of lacZ gene between SYBR Green I qPCR and QProbe-qPCR. However, SYBR Green I qPCR obtained somewhat higher copy number as $1{\times}10^8$ copies. It was decided that GTC/silica matrix extraction or magnetic beads beating in combination with SYBR Green I qPCR can be preferably applied for more effectively quantifying specific gene from a pure culture of microorganism.

A Bacteriocin of 5-kDa in Size Secreted by Bacillus subtilis 168 (Bacillus subtilis 168 균주가 분비하는 5 kDa 크기의 Bacteriocin)

  • Kwon, Gun-Hee;Lee, Hwang-A;Kim, Jeong-Hwan
    • Microbiology and Biotechnology Letters
    • /
    • v.38 no.2
    • /
    • pp.163-167
    • /
    • 2010
  • Bacillus subtilis 168 secreted antimicrobial substance(s) into culture medium and culture supernatant inhibited growth of some Gram positive bacteria. B. cereus and Listeria monocytogenes were the most sensitive organisms. The antimicrobial activity was destroyed when culture supernatant was treated by protease and proteinase K, indicating the proteinous nature of the substance (bacteriocin). The molecular weight of the bacteriocin was estimated to be 5 kDa by Tricine SDS-PAGE. B. cereus ATCC 14579 cells were killed when exposed to the bacteriocin, indicating that the mode of inhibition was bacteriocidal. These results show that B. subtilis 168 could be useful as a starter for fermented foods such as cheonggukjang where B. cereus contamination is a major concern.

Characteristics of Hemolysin in Mosquitocidal Bacillus thuringiensis strain 21-2 (모기 살충성 Bacillus thuringiensis 21-2균주의 용혈성 내독소 단백질의 특성)

  • 김광현;김위종;김영희;김병우
    • Microbiology and Biotechnology Letters
    • /
    • v.30 no.3
    • /
    • pp.230-234
    • /
    • 2002
  • To describe characteristics of a hemolysin in mosquitocidal Bacillus thuringiensis subsp. gyangiensis strain 21-2, Escherichia coli HB101 was transformed with a gene encoding hemolysin in the strain 21-2. Transformant 47 con-tained 2.5 kb DNA was selected by ELISA, immunoblot and DNA electrophoresis. Transformant 47-5 was recon-structed after digestion of the 2.5 kb DNA with Hind m. Transformant 47-5 contained 1.8 kb DNA and expressed 23 kDa Protein which had mosquitocidal activity to Aedes aegypti. The 23 kDa Protein itself in vitro didn't show hemolytic activity on human erythrocytes, but the protein had the activity after proteinase K treatment.