• BMB Reports
• /
• 제33권5호
• /
• pp.366-369
• /
• 2000

The nucleotide effects of Hafnia alvei aspartase were investigated. Purine nucleosides, such as adenosine and guanosine, increased the aspartase activities; whereas, purine nucleotides, such as AMP, ATP, GTP and IMP, caused little change in the aspartase activities. However, pyrimidine derivatives, such as cytidine and CTP, decreased the aspartase activity. The nucleotide and nucleoside effects by the limited trypsin-treated aspartase were similar to those of a native enzyme. These results indicate that the COOH-terminal region and an allosteric site might be located away from each other. The initial velocity study in the presence of adenosine showed that $K_m$ for aspartate was decreased to one-sixth of that in the absence of adenosine, but $V_{max}$ was unchanged. The significance of the distinct allosteric effect for the enzyme-nucleotide interaction is discussed.

• Journal of Photoscience
• /
• 제3권2호
• /
• pp.71-76
• /
• 1996

Anil K. Singh, Mrunalini M. Kapil, Department of Chemistry, Indian Institute of Technology Bombay - 400076, INDIA Purple membrane (PM, $\lambda$$_{max}$ 570 nm) of H. halobium on treatment with sulphuric acid changes its colour to blue ($\lambda$$_{max}$ 608 nm). The purple chromophore can be regenerated from the blue chromophore by exogeneous addition of anions such as CI$^-$ and HPO$_4^{2-}$. Chloride ion is found to be more effective than the dibasic phosphate ion in regenerating the purple chromophore. Nevertheless, one thing common to the anion regeneration is that both CI$^-$ and HPO$_4^{2-}$ show marked pH effect. At pH 1.0 the efficiency of regeneration of the purple chromophore is greater than at pH 2.0, for the same anion concentration. Fluorescence and circular dichroic studies indicate that the proteins do not undergo drastic changes at the secondary' or tertiary structure level and the native structure is preserved during this transition. However, chromophoric-site interactions between retinal and the apoprotein are affected during this colour transition. A molecular mechanism is advanced for this transition.

• EDISON SW 활용 경진대회 논문집
• /
• 제4회(2015년)
• /
• pp.70-75
• /
• 2015

Fasciclin 1 (FAS1) is an extracellular protein whose aggregation in cornea leads to visual impairment. While a number of FAS1 mutants have been studied that exhibit enhanced/decreased aggregation propensity, no structural information has been provided so far that is associated with distinct aggregation potential. In this study, we have investigated the structural and thermodynamic characteristics of the wild-type FAS1 and its two mutants, R555Q and R555W, by using molecular dynamics simulations and three-dimensional reference interaction site model (3D-RISM) theory. We find that the hydrophobic solvent accessible surface area increases due to hydrophobic core repacking in the C-terminus caused by the mutation. We also find that the solvation free energy of the mutants increases due to the enhanced non-native H-bonding. These structural and thermodynamic changes upon mutation contribute to understand the aggregation of these mutants.

• 대한안전경영과학회지
• /
• 제1권1호
• /
• pp.259-272
• /
• 1999

In order to enhance the selectivity, productivity and yield of methyl fructoside, which was synthesized by enzymatic glycosylation of sucrose and methanol solution, controlling of surface property of solid support using different immobilization procedures optimized microenvironment of immobilized invertase. Silanization and polyethylene imine coating methods were adopted to give a hydrophobic and hydrophilic environment of immobilized invertase. As a result, polyethyleneimine coating method gave higher loading of enzyme, effective activity, and relative activity than silanization method, because it brought on increasing the functional density of amino group and enhancing the conservation of activity by regulating of hydrophilicity. And then, hydrophilic environment was possible to restraint the assessing of methyl fructoside molecule, which was more hydrophobic than sucrose, fructose, and glucose molecule in the reaction mixture, into .the active site of immobilizedinvertase. Consequently, hydrophilic microenvironment of immobilized invertase by polyethyleneimine coating obtained higher yield and productivity with increasing conversion than silanized and native invertase. Thus, this procedure optimized the microenvironment of immobilized invertase suitable for the enzymatic synthesis of methyl fructoside.

• 한국생물물리학회:학술대회논문집
• /
• 한국생물물리학회 1996년도 정기총회 및 학술발표회
• /
• pp.4-4
• /
• 1996

$\alpha$$_1$-arantitrypsin, a member of the serpin (serine protease inhibitor) family, undergoes a large structural rearrangement upon the cleavage and insertion of the reactive site loop. This conformational change is driven by the metastability of the native serpin structures and has an important role in the regulation of the inhibitory-serpin function. (omitted)

• 대한화장품학회지
• /
• 제26권1호
• /
• pp.81-92
• /
• 2000

Development of stabilized enzyme was attempted for cosmetic applications. Papain, a proteolytic enzyme, was stabilized through conjugation with a soluble carbohydrate biopolymer, SC-glucan$^{TM}$ . With a novel structure of the conjugation site, stability of the enzyme was significantly enhanced such that more than 90% of the initial activity retained after a month storage at 45$^{\circ}C$, while no activity were detected in native enzyme or enzyme simply mixed with SC-glucan$^{TM}$ after the storage. Conjugation with SC-glucan$^{TM}$ not only extended the half-life of the enzyme on storage at higher temperature, but was also found to protect enzymes against some components contained in cosmetic products for skin care. Cosmetic lotion containing 1 % papain conjugate was more effective and less irritative in exfoliating stratum corneum of human skin than the lotion containing 5% lactic acid, one of the current popular exfoliating agents.gents.

• Bulletin of the Korean Chemical Society
• /
• 제26권5호
• /
• pp.740-746
• /
• 2005

In this article, we report the tandem mass spectrometry investigations for the electron capture efficiencies of the protons belonging to the different locations (generations) in a poly(propylene imine) dendrimer with three layers of a repeat unit (named as the third generation dendrimer). The employed tandem mass spectrometry methods include SORI-CAD (sustained off-resonance irradiation collisional activation dissociation) and ECD(electron capture dissociation) mass spectrometry. We obtained SORI-CAD spectra for the dendrimer ions in the different charge states, ranging from 2+ to 4+. The analysis of fragmentation sites provides the information as to where the protons are distributed among various generations of the dendrimer. Based upon this, a new strategy to study the electron capture efficiencies of the protons is utilized to examine a new type of triplycharged ions by SORI-CAD, i.e., the 3+ ions generated from the charge reduction of the native 4+ ions by ECD: (M+4H)$^{4+}\;+\;e^-\;{\rightarrow}$ (M+4H)$^{3+\bullet}$ ${\rightarrow}\;({H^{\bullet}}_{ejected}$) + (M+3H)$^{3+}\;\rightarrow$ CAD. Interestingly, comparison of these four SORICAD spectra indicates that the proton distribution in the charge-reduced 3+ ions is very close to that in the native 4+ ions. It further suggests that in this synthetic polymer ($\sim$1.7 kDa) with an artificial architecture, the electron capture efficiencies of the protons are actually insensitive to where they are located in the molecule. This is somewhat contradictory to common expectations that the protons in the inner generations may not be well exposed to the incoming electron irradiation as much as the outer ones are, thus may be less efficient for electron capture. This finding may carry some implications for the case of medium sized peptide ions with similar masses, which are known to show no obvious site-specific fragmentations in ECD MS.

• 한국임상수의학회지
• /
• 제29권1호
• /
• pp.112-117
• /
• 2012

This report evaluated the convenience and accessibility of a penile translocation surgery in the lateral recumbency of a calf using a tilt-up mobile compared with that of dorsal recumbency on the ground of a barn. One nine-month-old F-1 (Korean native sire x Holstein dam) calf was sedated with xylazine (0.03 mg/kg, IV) and restrained in the right lateral recumbency position on a tilt-up restraint mobile (90 cm high), whereas the other nine-month-old Korean native calf was administered xylazine (0.3 mg/kg, IV) and restrained in dorsal recumbency position on the ground of a barn, with assistance by one person. For the two calves, lidocaine was administered subcutaneously from the preputial orifice to the S-shaped penis. The preputial orifice was incised, and the preputial sheath and penis were separated bluntly, then laterally translocated to the site toward the left flank at a $40^{\circ}$ angle. Anti-inflammatory drug (ketoprofen) and antibiotics (penicillin) were administered following the surgery. The duration of surgery was 30 min shorter in the calf that received the surgery in lateral recumbency using the tilt-up mobile with operator's standing posture (60 min) than the one that underwent surgery in dorsal recumbency on the ground with operator's bending posture (90 min). One week after the surgery, the operation area, including the translocated preputial orifice, was healed without complications in both cases. The results detailed in this report demonstrate that penile translocation surgery in the lateral recumbency position using a tilt-up mobile might be used conveniently in calves due to the convenience of restraint, reduced surgery time, and reduced physical inconvenience for the surgeon.

• Molecules and Cells
• /
• 제26권1호
• /
• pp.34-40
• /
• 2008

To express an increased level of recombinant Mefp1 (marine mussel adhesive protein) in soluble form, we constructed expression vectors encoding truncated OmpA signal peptide-Mefp1 fusion proteins. OmpA signal peptide (OmpASP) is the 21 residue peptide fragment of the 23 residue OmpA signal sequence cleavable by signal peptidase I. We successfully produced increased levels of soluble recombinant Mefp1 (rMefp1) with various deletions of OmpASP, and found that the increased expression was caused by the increased pI of the N-terminus of the fusion proteins (${\geq}10.55$). All the OmpA signal peptide segments of 3-21 amino acids in length had the same pI value (10.55). Our results suggest that the pI value of the truncated OmpASP ($OmpASP_{tr}$) play an important role in directional signaling for the fusion protein, but we found no evidence for the presence of a secretion enhancer in OmpASP. For practical applications, we increased the expression of soluble rMefp1 with $OmpASP_{tr}$ peptides as directional signals, and obtained rMefp1 with the native amino terminus (nN-rMefp1) using an $OmpASP_{tr}$ Xa leader sequence that contains the recognition site for Xa protease.

• 한국산림과학회지
• /
• 제94권6호
• /
• pp.397-401
• /
• 2005

개비자나무로부터 추출한 HHT(homoharringonine)는 현재 가능성 있는 암화학요법제로 주목받고 있다. 국내 개비자나무 8개 천연집단의 HHT 함량 변이는 HPLC(high performance liquid chromatography)를 이용하여 조사하였고, 집단간 변이와 개체내의 부위별(잎, 줄기, 뿌리 및 종자) 변이 및 수령과 생장특성에 따른 함량 변이를 비교 분석하였다. 개비자나무의 집단간 HHT 함량 변이는 집단간에 통계적으로 유의한 차이가 인정되었으며, 거창의 남덕 유산 집단이 $1,048{\mu}g/g$으로 가장 높았고 완도의 오봉산 집단이 가장 낮았다. 개체내 부위별 함량은 잎에서 $874{\mu}g/g$으로 가장 높았으며, 다음으로 뿌리, 줄기, 종자 순으로 나타났다. 개비자나무의 HHT 함량은 수령이 증가하고 생장이 왕성해 질수록 대략 30% 정도 감소하는 것으로 나타났다.