• Korean Journal of Medicinal Crop Science
• /
• v.12 no.1
• /
• pp.1-9
• /
• 2004

Prolyl endopeptidase (PEP) is proline-specific serine protease, cleaving peptide bonds on the biologically active neuropeptides such as substance P, vassopressin, and thyrotropin-releasing hormone and is, therefore, suggested to play important roles in learning and memory process. In this work, the inhibitory effect of plant extracts on PEP was investigated. Out of 200 plant extracts, Prunus mume, Pyrola. japonica, Hypericum ascyron, Astilbe chinensis var. typica, and Elaeagnus umbellata inhibited more than 90% of PEP activity at the concentration of 5 ppm.

• YAKHAK HOEJI
• /
• v.41 no.2
• /
• pp.153-160
• /
• 1997

One hundred and seventy crude drugs were screened for prolyl endopeptidase (PEP) inhibitors. Among them, 80% methanolic extract of 18 medicinal plants such as Polygonum cuspi data, Sanguisorba officinalis, Eugenia caryophyllata, Rubus coreanus, Cinnamomum cassia (Cassiae Cortex and Cinammomi Ramulus), Rheum palmatum, Ulmus pumila, Sorbus commixta, Areca catechu, Uncaria sinensis, Terminalia chebula, Caesalpinia sappan, Nelumbo nucifera, Machilus thunbergii, Paeonia moutan, Elscholtzia patrini and Cynomorium coccineum inhibited more than 70% of PEP activity at a concentration of 40 ppm. The active principles of P. moutan, M. thunbergii, T chebula, A. catechu, S. commixta, R. palmatum, R. coreanus, E. caryophyllata and P. cuspidata were transferred into organic solvents, which showed more than 75% inhibition at 5 ppm.

• Journal of Applied Biological Chemistry
• /
• v.49 no.3
• /
• pp.110-113
• /
• 2006

Prolyl endopeptidase (PEP, EC 3.4.21.26, also referred to as prolyl oligopeptidase) degrades proline containing, biologically active neuropeptides such as vasopressin, substance P and thyrotropin-releasing hormone by cleaving peptide bonds on carboxyl side of prolyl residue within neuropeptides of less than 30 amino acids. Evaluation of PEP levels in postmortem brains of Alzheimer's disease patients revealed significant increases in PEP activity. Therefore, a specific PEP inhibitor can be a good candidate of drug against memory loss. Upon our examination for PEP inhibitory activity from micronutrients, ascorbic acid (vitamin C) showed small but significant PEP inhibition (13% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$). Palmitic acid showed almost no PEP inhibition. However, 6-O-palmitoyl ascorbic acid ($\underline{1}$) showed 70% PEP inhibition at $8{\mu}g{\cdot}ml^{-1}$ indicating that hydrophobic portion of the compound $\underline{1}$ may facilitate the inhibitory effect. $IC_{50}$ value of compound $\underline{1}$ was $12.6{\pm}0.2{\mu}M$. The primary and secondary Lineweaver Burk and Dixon plots for compound $\underline{1}$ indicated that it is a non-competitive inhibitor with inhibition constant (Ki) value of $23.7{\mu}M$.

• Applied Biological Chemistry
• /
• v.42 no.4
• /
• pp.351-355
• /
• 1999

In order to find anti-dementia drugs from natural products, prolyl endopeptidase inhibitors were purified from Puerariae Flos by consecutive solvent partition, followed by silica gel, Sephadex LH-20, and HPLC. Four isoflavonoid inhibitors were isolated and identified as tectorigenin, genistein, 5,7-dihydroxy-4',6-dimethoxyisoflavone, and 5-hydroxy-6,7,4'-trimethoxyisoflavone by means of instrumental analyses including $^{1}H-$, $^{13}C-$, $^{2}D-NMR$ and MS and $IC_{50}$ values against PEP were 5.30 ppm$(17.7\;{\mu}M)$, 10.39 ppm$(38.5\;{\mu}M)$, 13.92 ppm$(44.3\;{\mu}M)$, and 20.61 ppm$(62.8\;{\mu}M)$, respectively. Some previous mistakes in $^{13}C-NMR$ assignment were revised by careful investigation of HMBC and HMQC data.

• The Korean Journal of Community Living Science
• /
• v.16 no.4
• /
• pp.95-102
• /
• 2005

The present study was performed to investigate the 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging and Proly1 endopeptidase (PEP) inhibitory activities of plant extracts. The whole extract of Fragaria yezoensis inhibited the DPPH radical by $90.4\%$ and the stem of Gingko biloba, Gardenia jasminoides for. grandiflora and Rhododendron yedoensa var. poukhanene, the loaves of Rhododendron mucronulatum var. ciliatum, Gardenia jasminoides for. grandiflora and Corylus sieboldiana var. mandshurice, the fruit of Cornus officinalis, and the root of Gingko biloba showed high DPPH radical scavenging activities. In the case of PEP inhibitory activities, high inhibition was observed in the whole Plant of Fragaria ananassa, Fragaria yezoensis and Hypericum erectum, the stem of Actinidia arguta and Rhododendron yedoensa var. poukhanese, the leaves of Rhododendron yedoensa var. poukhanense and Rosa davurica, the fruit of Cornus officinalis. and the root of Acer okamotoanum. There was significant correlation (P=0.000) between DPPH radical scavenging and prolyl endopeptidase inhibitory activities, thus some of plant extracts such as whole Fragaria yezoensis, fruit of Cornus officinalis had high activities in both DPPH-scavenging and prolyl endopeptidase inhibition. Therefore, it is required to examine the mechanical interaction between DPPH-scavenging and prolyl endopeptidase inhibitory activities and further studying plant extracts with both these activities is desired to develop agents for preventing and treating of Alzheimer's disease.

• Journal of Applied Biological Chemistry
• /
• v.55 no.3
• /
• pp.195-198
• /
• 2012

Four chromone derivatives (1-4) were isolated from the clove buds (Syzygium aromaticum). Of these, two chromone C-glucosides (1 and 2) showed significant PEP inhibition with $IC_{50}$ values of $1.48{\pm}0.02$ and $1.74{\pm}0.03{\mu}M$ and $K_i$ values of $0.27{\pm}0.02$ and $0.50{\pm}0.05{\mu}M$, respectively. They also exhibited strong antioxidant capacities against the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt radical system with $EC_{50}$ values of $4.13{\pm}0.04$ and $4.79{\pm}0.03{\mu}M$, respectively.

• Microbiology and Biotechnology Letters
• /
• v.24 no.2
• /
• pp.191-196
• /
• 1996

The bacteriolytic enzyme produced from Bacillus subtilis SH-1 was purified and characterized, and its molecular weight was determined. The bacteriolytic enzyme activity was increased about 66.5 times via purification with recovery yield of 18.5%. The optimum pH and temperature of this enzyme were 9.0 and 50$\circ$C. The enzyme was stable within a pH range of 6.0-10.0 and unstable above 60 . The molecular weight of the enzyme was estimated to be 23,000 dalton in a form of monomer with no other subunits. Effect of the enzyme on the lysis of bacteria engaged in food posion was tested. The lysis degree was below 31% against Gram negative bacteria and above 48% in Gram positive bacteria. The values higher than 73% were obtained against Vibrio sp. and Listeria sp. As the turbidity of dissolved peptidoglycan clecreases, the free amino group levels were increased. And, based on hydrolysis of casein, this enzyme was thought to be an endopeptidase.

• Journal of Microbiology
• /
• v.41 no.1
• /
• pp.58-62
• /
• 2003

An extracellular pretense of Bacillus amyloliquefaciens S94 was purified to apparent homogeneity. The enzyme activity was strongly inhibited by general inhibitor for serine protease, PMSF, suggesting that the enzyme is a serine pretense. The purified enzyme activity was inhibited by leucine peptidase inhibitor, bestatin, suggesting that the enzyme is a leucine endopeptidase. The maximum proteolytic activity against different protein substrates occurred at pH 10, 45$^{\circ}C$ (protein substrate) and pH 8, 45$^{\circ}C$ (synthetic substrate). The purified enzyme was specific in that it readily hydrolyBed substrates with Leu or Lys residues at P$_1$ site. The pretense had characteristics of a cold-adapted protein, which was more active for the hydrolysis of synthetic substrate in the range of 15$^{\circ}C$ to 45$^{\circ}C$, specially at low temperature.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.6
• /
• pp.798-803
• /
• 1999

Prolyl endopeptidase [PEP; EC 3.4.21.26], a serine protease which is known to cleave peptide bonds on the carboxy side of a proline residue, plays an important role in the degradation of proline-containing neuropeptides that have been suggested to participate in learning and memory processes. An abnormal increase in the level of PEP, which can lead to generation of $A{\beta}$, is also suggested to be involved in Alzheimer's type senile dementia. In the course of screening PEP inhibitors from Basidiomycetes, the mushroom Polyozellus multiplex exhibited a high inhibitory activity against PEP. Two active compounds were isolated from the ethyl acetate soluble fraction by consecutive purification, using silica gel, Sephadex LH-20, and Lobar RP-18 chromatography. The chemical structures of these compounds were identified as thelephoric acid and 12-acety1-2,3,7,8-tetrahydroxy-[12H]-12-hydroxymethylbenzobis[I.2b,3.4b'] benzofuran-11-one (kynapcin-9) by spectral data including UV, IR, MS, HR-MS, $^1H-,{\;}^{13}C-$, and 2D-NMR. The $IC_{50}$ values of the thelephoric acid and kynapcin-9 were 0.157 ppm (446nM) and 0.087 ppm (212nM) and their inhibitor constants ($K_i$) were 0.73ppm ($2.09{\;}\mu\textrm{m}$) and 0.060 ppm (146 nM), respectively. Furthermore, they were non-competitive with a substrate in Dixon plots.

• Molecules and Cells
• /
• v.42 no.1
• /
• pp.79-86
• /
• 2019

Endolysins are bacteriophage-derived enzymes that hydrolyze the peptidoglycan of host bacteria. Endolysins are considered to be promising tools for the control of pathogenic bacteria. LysB4 is an endolysin produced by Bacillus cereus-infecting bacteriophage B4, and consists of an N-terminal enzymatic active domain (EAD) and a C-terminal cell wall binding domain (CBD). LysB4 was discovered for the first time as an L-alanoyl-D-glutamate endopeptidase with the ability to breakdown the peptidoglycan among B. cereus-infecting phages. To understand the activity of LysB4 at the molecular level, this study determined the X-ray crystal structure of the LysB4 EAD, using the full-length LysB4 endolysin. The LysB4 EAD has an active site that is typical of LAS-type enzymes, where $Zn^{2+}$ is tetrahedrally coordinated by three amino acid residues and one water molecule. Mutational studies identified essential residues that are involved in lytic activity. Based on the structural and biochemical information about LysB4, we suggest a ligand-docking model and a putative endopeptidase mechanism for the LysB4 EAD. These suggestions add insight into the molecular mechanism of the endolysin LysB4 in B. cereus-infecting phages.