• Korean Journal of Pharmacognosy
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• v.35 no.1 s.136
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• pp.16-21
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• 2004

Protein tyrosine phosphatase 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 compounds inhibiting PTP1B can improve insulin resistance and can be effective in treating type 2 diabetes and obesity. The methanol extracts of 160 herbal medicines were screened for the inhibitory activity against PTP1B. Among the tested extracts, methanol extracts of Amsonia elliptica, Areca catechu, Benincasa hispida, Morus alba, Salvia miltiorrhiza, Siegesbeckia orientalis, and Trichosanthes kirilowii showed relatively strong inhibitory activity against PTP1B.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.3
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• pp.293-303
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• 1999

The influences of specific protein phosphatase and protein kinase inhibitors on the ATP-sensitive $K^+\;(K_{ATP})$ channel-opening effect of pinacidil were investigated in single rat ventricular myocytes using patch clamp technique. In cell-attached patches, pinacidil $(100\;{\mu}M)$ induced the opening of the $K_{ATP}$ channel, which was blocked by the pretreatment with H-7 $(100\;{\mu}M)$ whereas enhanced by the pretreatment with genistein $(30\;{\mu}M)$ or tyrphostin A23 $(10\;{\mu}M)$. In inside-out patches, pinacidil $(10\;{\mu}M)$ activated the $K_{ATP}$ channels in the presence of ATP (0.3 mM) or AMP-PNP (0.3 mM) and in a partial rundown state. The effect of pinacidil $(10\;{\mu}M)$ was not affected by the pretreatment with protein tyrosine phosphatase 1B $(PTP1B,\;10\;{\mu}g\;ml^{-1}),$ but blocked by the pretreatment of protein phosphatase 2A $(PP2A,\;1\;U\;ml^{-1})$. In addition, pinacidil $(10\;{\mu}M)$ could not induce the opening of the reactivated $K_{ATP}$ channels in the presence of H-7 $(100\;{\mu}M)$ but enhanced it in the presence of ATP (1 mM) and genistein $(30\;{\mu}M).$ These results indicate that the $K_{ATP}$ channel-opening effect of pinacidil is not mediated via phosphorylation of $K_{ATP}$ channel protein or associated protein, although it still requires the phosphorylation of serine/threonine residues as a prerequisite condition.

• Biomolecules & Therapeutics
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• v.8 no.2
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• pp.153-159
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• 2000

A novel serine/threonine protein phosphatase with EF-hand motif, which belongs to PPEF family was partially cloned from rat brain cDNA by employing RT-PCR method. The size of the amplified clone was 1.6kbp. The amplified DNA was subcloned into pGEM-T-Easy vector and the resulting plasmid was maned as pGEM-rPPEF2. The nucleuotide sequence is shared by 88% with that of mouse PPEF-2 cDNA, and the deduced amino acid sequence reveal 92% homology with that of mouse PPEF-2 cDNA. The N-terminal region of the cloned rat brain PPEF contains a putative phosphatase catalytic domain (PP domain) and the C-terminal region contains multiple $Ca^{2+}$ binding sites (EF region). The putative catalytic domin (PP) and the EF-hand motif (EF) regions were subcloned into pGEX4T-1 and were overexpressed in E. coli DH5 as glutathione-S-transferase (GST) fusion proteins. Expression of the desired fusion protein was identified by SDS-PAGE and also by immunoblot analysis using monoclonal antibody against GST. The recombinant proteins were purified by glutathione-agarose chromatography. This report is first to demonstrate the cloning of PPEF family from rat brain tissues. The clone reported here would be invaluable for the investigation of the role of this new type-phosphatase in rat brain.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1039-1042
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• 2009

RNA polymerase II C-terminal domain phosphatase 1 containing ubiquitin like domain (UBLCP1) has been identified as a regulatory molecule of RNA polymerase II. UBLCP1 consists of ubiquitin like domain (UBL) and phosphatase domain homologous with UDP and CTD phosphatase. UBLCP1 was cloned into the E.coli expression vectors, pET32a and pGEX 4T-1 with TEV protease cleavage site and purified using both affinity and gel-filtration chromatography. Domains of UBLCP1 protein were successfully purified as 7 mg/500 mL (UBLCP1, 36.78 KDa), 32 mg/500 mL (UBL, 9 KDa) and 8 mg/500 mL (phosphatase domain, 25 KDa) yielded in LB medium, respectively. Isotope-labeled samples including triple-labeled ($^2H/^{15}N/^{13}C$) UBLCP1 were also prepared for hetero-nuclear NMR experiments. $^{15}N-^{1}H$ 2D-HSQC spectra of UBLCP1 suggest that both UBL and phosphatase domain are properly folded and structurally independent each other. These data will promise us further structural investigation of UBLCP1 by NMR spectroscopy and/or X-ray crystallography.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.724-730
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• 1998

Effects of raw soy flour(RSY) and black(RSB) feeding on protein concentration of liver and serum, and GOT, GPT and alkaline phosphatase activities of serum in diabetic and nondiabetic rats were studied. Male rats(Sprague-Dawley), mean weight of (338.4$\pm$19.2g) were assigned to six dietary groups and fed with the assigned diet for 28 days. For each experimental, some rats were injected with streptozotocin intraperitoneally(L.P.) to induce diabets, and other rats were injected with buffer L.P. as a control group. The liver, kidney and spleen weights relative to bo요 weigth were higher in raw yellow soy flour diet diabetes(D-RSY) and black soy flour diet diabetes(D-RSB) groups than control, but the body weights were lower than control. The protein and albumin concentrations of liver and serum were lower in D-RSY and D-RSB groups than control. The albumin concentration of serum in D-RSB group was lower than control. The GOT activities of serum in RSY and RSB groups were increased compared with control, but the GPT activities were lower in diabetic control, D-RSY and D-RSB groups than control. The alkaline phosphatase activities of serum in RSY and RSB groups were higher than control, but those in D-RSY and D-RSB groups were lower than diabetic control.

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1479-1484
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• 2008

Protein tyrosine phosphatase (PTP) 1B is the superfamily of PTPs and a negative regulator of multiple receptor tyrosine kinases (RTKs). Inhibition of protein tyrosine phosphatase 1B (PTP1B) has been proposed as a strategy for the treatment of type 2 diabetes and obesity. Recently, it has been reported that amentoflavone, a biflavonoid extracted from Selaginella tamariscina, inhibited PTP1B. In the present study, docking model between amentoflavone and PTP1B was determined using automated docking study. Based on this docking model and the interactions between the known inhibitors and PTP1B, we determined multiple pharmacophore maps which consisted of five features, two hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. Using receptor-oriented pharmacophore-based in silico screening, we searched the biflavonoid database including 40 naturally occurring biflavonoids. From these results, it can be proposed that two biflavonoids, sumaflavone and tetrahydroamentoflavone can be potent allosteric inhibitors, and the linkage at 5',8''-position of two flavones and a hydroxyl group at 4'-position are the critical factors for their allosteric inhibition. This study will be helpful to understand the mechanism of allosteric inhibition of PTP1B by biflavonoids and give insights to develop potent inhibitors of PTP1B.

• Korean Journal of Pharmacognosy
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• v.44 no.2
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• pp.176-181
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• 2013

In order to search for protein tyrosine phosphatase 1B (PTP1B) inhibitors as therapy of type 2 diabetes and obesity from Korean traditional prescriptions, we selected 58 traditional prescriptions based on a review of the Korean traditional medicine books. The hot water extracts of Korean traditional prescriptions were screened for the inhibitory activity against PTP1B. Among the tested extracts, water extracts of Jakgamhwangsinbu-tang, Seonbanghwalmyung-eum, and Takreeonjoong-tang showed relatively good inhibitory activity against PTP1B at the concentration of $30{\mu}g/ml$. Additionally, we evaluated PTP1B inhibitory effect for each herbal ingredient and composition in Jakgamhwangsinbu-tang (芍甘黃辛附湯). Of the tested ingredients from this herbal medicine, water extracts of Paeoniae Radix rubra and Rhei Rhizoma, and ethanol extracts of Paeoniae Radix alba, Rhei Rhizoma, Asiasari Radix, and Aconiti Tuber showed good PTP1B inhibitory effect. Herbal compositions composed of these active herbal ingredients exhibited significant activity for PTP1B inhibition over 70% at $7.5{\mu}g/ml$.

• The Korean Journal of Mycology
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• v.25 no.2 s.81
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• pp.85-90
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• 1997

The Isozyme activities of Lentinula edodes were studied as a preliminary study for genetic analysis after protoplast fusion. The presence of peroxidase, esterase, superoxide dismutase, acid phosphatase, alkaline phosphatase, alcohol dehydrogenase and ${\alpha}-amylase$ was examined. An intracellular buffer-soluble protein from the mycelia was used for enzyme analysis on nondenaturing polyacrylamide gels. The auxotrophs of Lentinula edodes were positive for peroxidase, esterase, superoxide dismutase and acid phosphatase. However, alkaline phosphatase, alcohol dehydrogenase and ${\alpha}-amylase$ were not detected. The esterase and peroxidase were not affected by the various culture age. Isozyme identification may be a useful tool after protoplast fusion.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.418-421
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• 2000

A new direct colorimetric assay of microcystin in water and algal samples is proposed consisting of two procedures as follows: 1) the elimination of phosphorus in the sample and concentration of microcystin using a C(sub)18 cartridge, 2) the detection of the released phosphorus by the ascorbic acid method and determination of protein phosphatase (PP) inhibition by microcystin. The optimum amounts of phosphorylase ${\alpha}$ and PP-1 in 50 ${\mu}$L concentrated sample were 50$\mu\textrm{g}$/50${\mu}$L buffer and 1.0unit/50${\mu}$L buffer, respectively, for the best assay. The pH for the maximum activity of PP-1 was 8. The minimum detectable concentration for this method was about 0.02$\mu\textrm{g}$/L, which is sufficient to meet the proposed guideline level of 1$\mu\textrm{g}$ microcystin/L in drinking water. Consequently, it would seem that the proposed direct colorimetric assay using PP is a rapid, easy, and convenient method for the detection of microcystin in water and algal samples.

• Journal of Microbiology and Biotechnology
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• v.30 no.2
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• pp.306-312
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• 2020

Despite the importance of brown adipocytes as a therapeutic target for the prevention and treatment of obesity, the molecular mechanism underlying brown adipocyte differentiation is not fully understood. In particular, the role of post-translational modifications in brown adipocyte differentiation has not been extensively studied. Histidine phosphorylation is increasingly recognized an important process for protein post-translational modifications. In this study, we show that histidine phosphorylation patterns change during brown adipocyte differentiation. In addition, the expression level of protein histidine phosphatase 1 (PHPT1), a major mammalian phosphohistidine phosphatase, is reduced rapidly at the early phase of differentiation and recovers at the later phase. During white adipocyte differentiation of 3T3-L1 preadipocytes, however, the expression level of PHPT1 do not significantly change. Knockdown of PHPT1 promotes brown adipocyte differentiation, whereas ectopic expression of PHPT1 suppresses brown adipocyte differentiation. These results collectively suggest that histidine phosphorylation is closely linked to brown adipocyte differentiation and could be a therapeutic target for obesity and related metabolic diseases.