• 한국수산과학회지
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• 제38권2호
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• pp.83-88
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• 2005

Protease inhibitors were purified from the eggs of Alaska pollock (Theragra chalcogramma) using the following purification steps: ammonium sulfate precipitation, ion exchange, gel permeation, and high performance liquid chromatographies (HPLC). The protease inhibitor from the heated eggs of Alaska pollock was not as well purified. In addition, the heated eggs showed lower specific inhibitory activity than the unheated eggs. The purification yields after ammonium sulfate precipitation, ion exchange, and gel permeation chromatographies were 22.7$\%,\;15.3\%$,and $4.4\%$, respectively. There were two kinds of protease inhibitors on the gel permeation chromatography pattern Their molecular weights were estimated to be 66,700 and 16,000 Da, respectively. Both were classified as a cysteine protease inhibitor because of the existence of inhibiting papain, which is one of cysteine proteases.

• Bulletin of the Korean Chemical Society
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• 제17권1호
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• pp.19-24
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• 1996

The potential energies of HIV-1 protease, inhibitor, and their complex have been calculated by molecular mechanics and the "binding energy", defined as the difference between the potential energy of complex and the sum of potential energies of HIV-1 protease and its inhibitor, has been compared to the free energy in inhibition reaction. The trend in these binding energies seems to agree with that in free energies.

• 한국동물학회지
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• 제31권4호
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• pp.295-299
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• 1988

An endogenous 17-6a inhibitor of Caa+_activated protease has been purified from neo-plastic tissues of human stomach using heat treahent and conventional chromatographir procedures. It appears to consist of a single polvpeptide since the same molecular weight was obtained by both gel fntration under nondenaturing condition and gel electrophoresis in the presence of SDS. Since the size of the inhibitor or is the smallest amens those reported so far, it may represent a functional unit for inhibiting Caa+_activated protease. This protein is also capable of inhibiting the protease isolated loom chick skeletal muscle. Thus, the functional unit of the inhibitor most well be conserved during evolution. Howrver, it remains unclear what may be the physiological significance of the presence of the Iow-molecular weight form of the inhibitor in neoplastic tissues of human stomach. 사람의 위암조직으로부터 Ca2)_activated protease을 저해하는 단백질을 열처리 및 여러 크로마토그라피 방법을 이용하여 순수분리 하였다. 이 저해단백질은SDS-전기영동카자1 filtra-tion의 방법에 의하여 그 분자량이 17 kDa으로 나타남으로 보아 단일 Polypeptide로 구성되어 있음을 알 수 있었다. 이 저해 단백질의 분자량은 지금까지 알려진 CaB+_activated protease의 저해단백질에 비하여 가장 작은 것이었다. 따라서, 이 단.백질은 Ca2)에 의하여 활성화되는 단백질 분해효소의 작용을 저해하는 기능적 단위로 추측되었다. 한편, 이 저해제는 계 골격근에서 추출한 Ca2+ _activated protease의 촹성 도 억제 하는 것으로 나타났다. 이러 한 결과는 이 저 해 단백질의 기능적 단위가 진화과정 동안 오래 보존되어 왔음을 시사한다. 그러나, 사람의 위암조직에서 이 저해제가 무슨 이유로 가장 작은 분자량의 단백질로 존재하는지에 대한 생리학적 중요성에 관한 문제는 앞으로 많이 연구되어져 야 할 것이다.

• 한국식품영양과학회지
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• 제37권3호
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• pp.373-378
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• 2008

광양만의 해안 뻘에서 protease 저해력이 우수한 균주 S. thermocarboxydus C12를 분리하여 최적의 저해제 생산 조건을 조사하였다. 최대 저해활성을 보이는 온도와 초기 pH는 각각 $40^{\circ}C$와 8.0이었다. 저해제 생산에 미치는 탄소원의 영향을 검토한 결과, 단당류인 galactose, glucose, fructose와 다당류인 starch에서 높은 저해활성을 보였으며, 최적의 탄소원과 농도는 각각 galactose와 1.6%(w/v)였다. 질소원의 경우 복합배지인 polypeptone과 proteose peptone에서 가장 높은 저해활성이 나타났으며, 최적의 농도와 질소원은 0.5%(w/v)와 proteose peptone이었다. 최적의 NaCl 농도와 금속이온은 각각 1%(w/v)와 1 mM LiCl이었다. 선정된 최적배양조건에서 균주를 배양한 결과, 84시간 동안 배양 시 저해활성이 최대인 것으로 나타났다.

• 한국식품영양학회지
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• 제11권6호
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• pp.673-677
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• 1998

A inhibitor acting on substrate proteolytic enzyme was isolated from culture broth of Streptomyces sp. SK-862, which had been isolated from soil in Wonju City, by using the colloidal agar medium. The optimum culture temperature and initial pH for the production of the protease inhibitor was 28$^{\circ}C$ and pH 8.5, respectively. The optimum culture medium was composed of 1.5% glucose, 0.5% peptone, 0.1% K2PHO4, 0.05% CaCO3 and initial pH 8.5. The inhibitor production was maximum when the strain was incubated in shaking incubator at 70 strokes for 60 hours.

• Bulletin of the Korean Chemical Society
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• 제20권3호
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• pp.301-306
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• 1999

Hepatitis C virus (HCV) has been known to be an enveloped virus with a positive strand RNA genome and the major agent of the vast majority of transfusion associated cases of hepatitis. For viral replication, HCV structural proteins are first processed by host cell signal peptidases and NS2/NS3 site of the nonstructural protein is cleaved by a zinc-dependent protease NS2 with N-terminal NS3. The four remaining junctions are cleaved by a separate NS3 protease. The solution conformations of NS4B/5A, NS5A/5B substrates and NS5A/5B inhibitor have been determined by two-dimensional nuclear magnetic resonance (NMR) spectroscopy. NMR data suggested that the both NS5A/5B substrate and inhibitor appeared to have a folded tum-like conformation not only between P1 and P6 position but also C-terminal region, whereas the NS4B/5A substrate exhibited mostly extended conformation. In addition, we have found that the conformation of the NS5A/5B inhibitor slightly differs from that of NS5A/5B substrate peptide, suggesting different binding mode for NS3 protease. These findings will be of importance for designing efficient inhibitor to suppress HCV processing.

• 대한바이러스학회지
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• 제30권3호
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• pp.161-170
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• 2000

Continuous efforts are being made to find effective therapeutic agents against HIV-1, the causative agents of AIDS. In this study, we developed a cell-based assay system employing a trans-complementation for production of recombinant viruses which are capable of undergoing one round of replication in CD4+ T cells. This assay system was tested for ability to screen the agents that act at late stage of HIV-1 life cycle. The effect of a protease inhibitor on the trans-complementation assay was assessed. Recombinant HIV-1 viruses were prepared from a trans-complementation in the presence of various concentrations of protease inhibitor. Inhibition of single round infection of these recombinant viruses by protease inhibitor was observed to be a dose-dependent manner. Inhibitory effects of a protease inhibitor on HIV-1 Gag polyprotein processing by HIV-1 protease was detected at concentrations of the protease inhibitor compatible with inhibition of virus infection, confirming that the corresponding step was involved in the inhibitory mechanism of this compound. Together, these results provide evidence that a cell-based assay system established in this study can be used to screen the agents that target the late stage of HIV-1 life cycle.

• Applied Biological Chemistry
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• 제41권8호
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• pp.563-567
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• 1998

Computer aided molecular modeling can help to predict the three dimensional structure of the polypeptide without the sample. The study on soybean Bowman-Birk protease inhibitor (SBI) is valuable, because it has been recently known that SBI possesses anticarcinogenic activities and immune-stimulating properties. SBI has several isoinhibitors, whose isolation and characterization were reported in 1990. Among these, DII inhibits trypsin only. The different inhibitory specificities cannot be explained only by their different primary sequences, but is possible with further assistance by the study on their different three dimensional structures. The study on the three dimensional structure of DII using homology method is reported in this paper.

• Journal of Microbiology
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• 제33권2호
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• pp.103-108
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• 1995

Streptomyces fradiae protease inhibitor (SFI) was purified effectively by preparative isoelectric focusing and hydroxyapatite chromatography. The molecular weight of SFI was estimated to be 1.7 kDa by SDS-PAGE and 1.8 kDa by molecular sieving HPLC. One hundred and sixty amino acid residues were determined from which molecular weight of SFI was calculated to be 17.054 Da and carbohydrate residue was not detected. SFI was calculated to be 17,064 Da and carbohydrate residue was not detected. SFI was a monomeric protein with two reactive sits, of which isoelectric point was pH 4.1. N-terminal amino acid sequence of SFI had homology with SSI (Streptomyces subsilisin inhibitor) and other protease inhibitors produced by Streptomyces.

• 한국수산과학회지
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• 제46권4호
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• pp.351-358
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• 2013

A protease inhibitor from fish eggs was fractionated using chromatographic methods. The fractionation efficiency was evaluated in terms of specific inhibitory activity (SIA, U/mg), purity (fold), total inhibitory activity (TIA, U), and recovery (%). The protease inhibitor (PI) from egg extracts of skipjack tuna (ST Katsuwonus pelamis), yellowfin tuna (YT Thunnus albacares) and Alaska pollock (AP Theragra chalcogramma) was fractionated using Sephadex G-50 gel filtration and DEAE-Sepharose CL-6B anion exchange chromatography based on protein size exclusion and net charge, respectively. Fractions exhibiting strong inhibitory activity were contained in the 30-50 kDa fraction on gel filtration and in the range of 0.4-0.7 M NaCl gradient fraction on anion exchange chromatography. The respective TIA and percent recovery of the fraction obtained with gel filtration toward trypsin and $N{\alpha}$-benzoyl-L-arginine-p-nitroanilide (BAPNA) were 2,758.7 U and 29.6% for ST, 1,005.5 U and 25.6% for YT, and 1,267.5 U and 26.0% for AP. Gel filtration chromatography was more effective at fractionating PI than using ion exchange chromatography. These results suggest that fish eggs act as serine protease inhibitors and might be useful for protease inhibition in foodstuffs.