• BMB Reports
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• v.29 no.4
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• pp.386-392
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• 1996

A Saccharomyces cerevisiae Protein Tyrosine Phosphatase, PTP1, was expressed from an Escherichia coli expression system and milligram quantities of active PTP1 were purified chromatographically. The substrate specificity of the recombinant PTP1 was probed using synthetic phosphotyrosine-containing peptides corresponding to the regulatory phosphorylation sites of the yeast MAP kinase homologues $Fus3_{176-186}$, $Kss1_{179-189}$, and $Hog1_{170-180}$. Peptide sequences derived from the MAP kinase homologues were chosen arbitrarily as starting points for sequence variation studies even though they are not likely to be candidates for physiological substrates of PTP1. Phosphotyrosyl-$Hog1_{170-180}$ peptide showed a $K_M$ value of 877 ${\mu}M$ and phosphorylated $Kss1_{179-189}$ and $Fus3_{176-186}$ peptides showed lower $K_M$ values of 74 ${\mu}M$ and 51 ${\mu}M$ each. To study the effect of sequence variations of the peptide, amino acids of the undecapeptide $Hog1_{170-180}$ (DPQMTGpYVSTR) were sequentially substituted by an alanine residue. More extensive variations of each amino acid revealed positional importance of each amino acid residue. Based on these results, we derived a peptide sequence (DADEpYDA) that is recognized by PTP1 with an affinity ($K_M$ is 4 ${\mu}M$) significantly higher than that of the peptides derived from the phosphorylation sites of Fus3, Kss1, and Hog1.

• Journal of Ginseng Research
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• v.38 no.1
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• pp.28-33
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• 2014

Background: Panax notoginseng has been used as a general tonic agent to invigorate human body for millennia in China and continued to be used until present. Methods: Some chromatographic methods were performed to isolate pure triterpenoids, and their structures were determined by nuclear magnetic resonance (NMR) experiments. Anti-diabetes activities of isolated compounds were evaluated through their inhibitory activity of protein tyrosine phosphatase 1B (PTP1B) enzyme. Results and Conclusion: Three new dammarane-type triterpenoids, notoginsenoside-LX (1), notoginsenoside-LY (2), and notoginsenoside-FZ (3) together with eighteen known compounds were isolated from the Panax notoginseng leaves. The structure-activity relationship of the compounds with dammaranetype triterpenoids and their PTP1B inhibitory activity were also reported. Results showed that compounds 2, 15, 20, and 21 can significantly inhibit the enzyme activity of PTP1B in a dose-dependent manner, with inhibitory concentration 50 ($IC_{50}$) values of $29.08{\mu}M$, $21.27{\mu}M$, $28.12{\mu}M$, and $26.59{\mu}M$, respectively. The results suggested that Panax notoginseng leaves might have potential as a new therapeutic agent for the treatment of diabetes.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.2
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• pp.109-115
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• 2008

The comparative molecular field analyses(CoMFA) models between the substituents with changing groups($R_1{\sim}R_4$) of $3{\beta}$-hydroxy-12-oleanen-28-oic acid derivatives as substrate molecule and their inhibitory activities($pI_{50}$) against protein tyrosine phosphatase(PTP)-1B were derived and discussed quantitatively. The optimized CoMFA F1 model have best predictability and fitness($r^2_{cv.}=0.654$ and $r^2_{ncv.}=0.995$). The order of contribution ratio (%) with CoMFA fields on the inhibitory activities was a steric field(53.0%), electrostatic field(36.2%) and hydrophobic field(10.8%). From the analytical results of CoMFA contour maps, the inhibitory activities were dependent on the R4 group in substrate molecules. Particularly, the new active compounds(P1 & P2) with the inhibitory activity against melanin synthesis were expected.

• Natural Product Sciences
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• v.13 no.4
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• pp.311-316
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• 2007

In this study, the twenty-four ethyl acetate extracts of twenty-two medicinal plants, traditionally used in Vietnam as anti-diabetes agents, were investigated for ${\alpha}$-amylase and protein tyrosine phosphatase 1B (PTP1B) enzymes inhibitory activity in vitro. The results indicated that, twelve materials (50.0%) showed moderate to strong inhibitory activity in ${\alpha}$-amylase inhibitory activity with $IC_{50}$ values ranging from 2.5 to $48.8{\mu}g/mL$; meanwhile, ten extracts (41.6%) could demonstrate PTP1B activity with $IC_{50}$ values less than $30.5{\mu}g/mL$. Some plants presented interesting activities against both of ${\alpha}$-amylase and PTP1B enzymes such as Catharanthus roseus, Carthamus tinctorius, Momordica charantia, Gynostemma pentaphyllum, Glycyrrhiza glabra, Smilax glabra, Psidium guajava (leave), and Rehmannia glutinosa. The study may provide a proof, at least in a part, for the ethno-medical use in diabetes disease of these plants.

• The Korea Journal of Herbology
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• v.37 no.1
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• pp.51-59
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• 2022

Objectives : The process through which mesenchymal cells condense and differentiate into chondrocytes to form new bone is known as endochondral bone formation. Chondrogenic differentiation and hypertrophy are essential steps in bone formation and are influenced by various factors. The stem bark and root bark of Eleutherococcus sessiliflorus (ES) have been widely used to treat growth retardation and arthritis in traditional Korean Medicine. In this study, we aimed to investigate the possible role of the stem bark of ES in the stimulation of chondrogenic differentiation in clonal murine chondrogenic ATDC5 cells. Methods : In ATDC5 cells treated with ES extract, cell viability and extracellular matrix production were determined using CCK-8 assay and Alcian blue staining, respectively, and alkaline phosphatase activity was measured. We also examined mRNA and protein expression levels of genes related to chondrogenic expression in ATDC5 cells using reverse transcription-polymerase chain reaction and western blot analyses. Results : ES extract increased the accumulation of Alcian blue-stained cartilage nodules and alkaline phosphatase activity in ATDC5 cells. It increased the mRNA expressions of chondrogenic markers including bone sialoprotein (BSP), cartilage collagens, Runt-related transcription factor-2 (RUNX-2), osteocalcin (OCN), β-catenin, and bone morphogenetic protein-2 (BMP-2), as well as the protein expressions of β-catenin, RUNX-2, BMP-2, and alkaline phosphatase (ALP). Conclusion : Taken together, these results suggest that ES extract exhibits a chondromodulating activity and therefore may be a possible agent for the treatment of bone growth disorders.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.405-411
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• 1985

The buffer soluble proteins were extracted from six cultivars of barley grains and analyzed by various electrophoresis; 7.5% polyacrylamide slab gel, 2-30% polyacrylamide porosity gradient tube gel, isoelectric focusing (pH4-9) and starch gel electrophoresis. The proteins, esterase, acid phosphatase, malate dehydrogenase, glutamate dehydrogenase and leucine aminopeptidase were investigated to find out the best method to differentiate barley cultivars. The result were that protein and esterase bands in 2-30% polyacrylamide porosity gradient tube gel electrophoresis and protein bands in 7.5% polyacrylamide slab gel electrophoresis showed typical varietal differences. Therefore, those methods were suitable for differentiation of barley cultivars. It was difficult to differentiate the cultivars by the other methodes and patterns of the other enzymes.

• Journal of Nutrition and Health
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• v.22 no.6
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• pp.497-506
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• 1989

To investigate the effect of levels of dietary protein and age on bone metabolism 40% and 5% casein were fed to the rats of 2 & 13 months of age for 12 weeks. High protein groups showed higher bone weight and Ca content than low protein groups and urinary Ca loss was increased in high protein groups but the difference disappeared gradually. A significant increase in urinary hydroxyproline excretion was noted in high protein groups of both age. Another short term study was undertaken to study if the above effect was related with renal function or PTH. Extremely high and low protein diets(60%, 6%) were fed to the rats of different ages(6wks, 6mos.) for 2 weeks, Urinary Ca excretion was significantly increased in high protein groups of young and aged rats and GFR was increased as well. There was no difference in serum iPTH levels between low and high protein groups, but it was elevated in aged rats. Alkaline phosphatase activity was higher in young rats, reflecting faster bone formation. The observed hypercalciuria in high protein groups, especially in aged rats, seems to be related to higher GFR, and PTH dose not appear to be a major mediator.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1532-1536
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• 2008

Quercetin which isolated form the roots of Houttuynia cordata. was determined on the basis of IR, ID and 2D NMR specta by direct comparison with authentic compounds. Protein tyrosine phophatase 1B (PTP1B) is thought to be a negative regulator in insulin signal-transduction pathway. Insulin-resistance by the activation of PTP1B is a hallmark of both type 2 diabetes and obesity. Thus, the compound inhibiting PTP1B can improve insulin resistance and can be effective in treating type 2 diabetes and obesity. Quercetin which measured the inhibitory activity against PTP1B was 92.1% inhibition in the 30 ${\mu}g$/mL, 83.4% inhibition in the 6 ${\mu}g$/mL and 76.5% inhibition in the 3 ${\mu}g$/mL. These results suggest that quercetin retains a potential PTP1B activity.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.878-895
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• 2017

Phosphorylation, a critical mechanism in biological systems, is estimated to be indispensable for about 30% of key biological activities, such as cell cycle progression, migration, and division. It is synergistically balanced by kinases and phosphatases, and any deviation from this balance leads to disease conditions. Pathway or biological activity-based abnormalities in phosphorylation and the type of involved phosphatase influence the outcome, and cause diverse diseases ranging from diabetes, rheumatoid arthritis, and numerous cancers. Protein tyrosine phosphatases (PTPs) are of prime importance in the process of dephosphorylation and catalyze several biological functions. Abnormal PTP activities are reported to result in several human diseases. Consequently, there is an increased demand for potential PTP inhibitory small molecules. Several strategies in structure-based drug designing techniques for potential inhibitory small molecules of PTPs have been explored along with traditional drug designing methods in order to overcome the hurdles in PTP inhibitor discovery. In this review, we discuss druggable PTPs and structure-based virtual screening efforts for successful PTP inhibitor design.

• BMB Reports
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• v.49 no.7
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• pp.370-375
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• 2016

Ras oncoproteins are small molecular weight GTPases known for their involvement in oncogenesis, which operate in a complex signaling network with multiple effectors. Approximately 25% of human tumors possess mutations in a member of this family. The Raf1/MEK/Erk1/2 pathway is one of the most intensively studied signaling mechanisms. Different levels of regulation account for the inactivation of MAP kinases by MAPK phosphatases in a cell type- and stimuli-dependent manner. In the present study, using three inducible Ras-expressing NIH/3T3 cell lines, we demonstrated that MKP3 upregulation requires the activation of the Erk1/2 pathway, which correlates with the shutdown of this pathway. We also demonstrated, by applying pharmacological inhibitors and effector mutants of Ras, that induction of MKP3 at the protein level is positively regulated by the oncogenic Ras/Raf/MEK/Erk1/2 signaling pathway.