• Title/Summary/Keyword: Competitive inhibitor

Search Result 195, Processing Time 0.031 seconds

Trypsin Inhibitor from Streptomyces sp. (Part 2) Biological Activities or the Inhibitor (Streptomyces 속 균주가 생성하는 Trypsin Inhibitor (제2보) 저해물질의 생물학적 작용상)

  • Yi, Dong-Heui;Seu, Jung-Hwn
    • Microbiology and Biotechnology Letters
    • /
    • v.10 no.4
    • /
    • pp.283-288
    • /
    • 1982
  • Trypsin inhibitor produced by Streptomyces sp. was investigated its reactive characteristics against trypsin. The mode of inhibition against trypsin was mixed type of non-competitive and competitive with casein, and enzyme-inhibitor complex was formed rapidly. The inhibitory activity was increased by the addition of isoleucine and depressed by silver, mercuric or cupric ion. And when egg albumin or hemoglobin was used as substrate for trypsin, the inhibition ratio was changed. The inhibitor inhibited coagulation of blood of bovine.

  • PDF

Characters of proteinase inhibitor isolated from streptomyces fradiae (Streptomyces fradiae에서 분리한 단백질 분해효소저해물질의 특성)

  • 정영화;이병규;이계준
    • Korean Journal of Microbiology
    • /
    • v.28 no.1
    • /
    • pp.65-70
    • /
    • 1990
  • The objective of the current study is to elucidate the biological roles of proteinase inhibitor in microorganisms. As the first step, a strain of Streptomyces fradiae was selected as a producer of extracellular proteinase inhibitor. The proteinase inhibitor was purified from culture broth through ultrafiltration, gel-filtration and ion-exchange chromatography. Molecular weight of the proteinase inhibitor was estimated to be 16, 800 by SDS polyacrylamide gel electrophoresis. It was found that the proteinase inhibitor inhibited only alkaline serine proteinases such as subtilisin, $\alpha$-chymotrypsin and Promase E but not trypsin and other proteinases. The mode of inhibition against Pronase E with succinyl-phenylalanine-p-nitroanilide as a substrate was competitive.

  • PDF

Kinetic Analysis of Purine Nucleoside Phosphorylase in Saccharomyces cerevisiae (Saccharomyces cerevisiae에서 얻은 Purine Nucleoside Phosphorylase의 반응 속도론적 분석)

  • Choi, Hye-Seon
    • Korean Journal of Microbiology
    • /
    • v.31 no.2
    • /
    • pp.148-156
    • /
    • 1993
  • Kinetic parameters of purine nucleoside phosphorylase (PNP) from Saccharomyces cerevisiae were measured. The Michaelis constants determined for substrates of the enzyme were $ 2.0 * 10^{-4}$ M for inosine, $2.0 *10^{-3}$ M for deoxyinosine, $ 2.0 * 10^{-5}$ M for guanosine and $2.0 10 ^{-5}$ M for deoxyguanosine. According to the ratio of relative $K_{cat}$Km, substrate specificity of each nucleoside was in the order of guanosine or deoxyguanosine, inosine and deoxyinosine. Cosubstrate, phosphate, revealed downward curvature in Lineweaver-Burk plot at high concentrations, indicating a negative cooperativity between subunits. The inhibition constants for purine analogs were measured to be $ 6 * 10^{-4}$ M for formycin B as the competitive inhibitor of inosine, $ 9 * 10^{-6}$ M for guanine as the competitive inhibitor of guanosine, $2 * 10^{-4}$ M for hypoxanthine as the non competitive inhibitor of guanosine and $4.5 * 10 ^{-4}$ M for 6-mercaptopurine as the non competitive inhibitor of guanosine. Alternative substrates, guanosine, deoxyguanosine and adenosine were found to act as competitive inhibitors with Ki values o $f^ 2.0 * 10 {-5}$ M, $2.6 * 10^{-5}$ M and $8.5 * 10 ^{-4}$ M, respectively, when inosine was the variable substrate. Guanosine and deoxyguanosine were also observed as competitive inhibitors with the Ki values of $1.8 * 10^{-5}$ M and $ 3.0 * 10^{-5}$ M, respectively, when deoxyinesine was the variable substrate. The results of alternative substrate sstudies suggested that a single enzyme acted on different nucleosides, inosine, deoxyinosine, adenosine, guanosine and deoxyguanosine.e.

  • PDF

Characterization of Thiol Protease Inhibitor Isolated from Streptornyces sp. KISl3 (Streptomyces sp. KIS13 균주에서 분리한 thiol계 단백질분해효소 저해물질의 특성)

  • 김인섭;이계준
    • Microbiology and Biotechnology Letters
    • /
    • v.18 no.5
    • /
    • pp.501-505
    • /
    • 1990
  • Streptomyces sp. KISl3 isolated from soil was found to produce low molecular weight thiol protease inhibitors. The protease inhibitor production was closely linked to the cell growth and regulated by growth condition. The inhibitor was purified from the culture broth through butanol extraction, silicagel 60 column chromatography, Sephadex LH-20 gel filtration and preparative HPLC. The inhibitor showed specific inhibitory activity to thiol protease such as papain, picin and bromelain. The mode of inhibition against papain to Hammersten casein as a substrate was non-competitive.

  • PDF

Isolation and Characterization of $\alpha$-Glucosidase Inhibitor from the Fungus Ganoderma lucidum

  • Kim, Shin-Duk;Nho, Hong Joon
    • Journal of Microbiology
    • /
    • v.42 no.3
    • /
    • pp.223-227
    • /
    • 2004
  • An ${\alpha}$-glucosidase inhibitor, SKG-3, was isolated from the fruiting bodies of Ganoderma lucidum and its physico-chemical properties were characterized. It was a highly specific and effective reversible inhibitor of ${\alpha}$-glucosidase. It showed very potent inhibitory activity against a-glucosidase with an IC$\sub$50/ value of 4.6$\mu\textrm{g}$/$m\ell$, but no activity for any other glycosidases tested. Enzyme activity could be recovered upon dialysis, thus providing evidence for the reversibility of the inhibition. A Lineweaver-Burk plot indicated that the SKG-3 inhibition of ${\alpha}$-glucosidase was competitive.

Hypocholesterolemic Soybean Peptide (IAVP) Inhibits HMG-CoA Reductase in a Competitive Manner

  • Pak, Valeriy V.;Koo, Min-Seon;Lee, Na-Ri;Oh, Su-Kyung;Kim, Myung-Sunny;Lee, Jong-Soo;Kwon, Dae-Young
    • Food Science and Biotechnology
    • /
    • v.14 no.6
    • /
    • pp.727-731
    • /
    • 2005
  • Synthesized Ile-Ala-Val-Pro (IAVP) peptide, which has the highest hypocholesterolemic effect among a number of synthesized derivatives of Ile-Ala-Val-Pro-Gly-Glu-Val-Ala (IAVPGEVA) isolated from 11S globulin of soy protein by pepsin digestion, was selected for investigation in the present study. Using a recombinant Syrian hamster 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), we studied in detail the inhibition of this enzyme by IAVP and compared the action of this peptide to that of lovastatin, a known competitive inhibitor of this enzyme. The concentration of IAVP required for 50% inhibition ($IC_{50}$) of HMGR activity in given experimental conditions was $340\;{\mu}M$. Kinetic analysis revealed that the studied peptide is a competitive inhibitor of HMGR with respect to both 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and nicotinamide adenine dinucleotide phosphate (NADPH), with an equilibrium constant of inhibitor binding ($K_i\;=\;[E][I]/[EI]$) of $61{\pm}1.2\;{\mu}M$ and $157{\pm}4.4\;{\mu}M$, respectively. At the same conditions, $K_i$ and $IC_{50}$ for lovastatin were $2.2{\pm}0.1\;nM$ and 12.5 nM, respectively. Thus, the given peptide interacts with HMGR as a bisubstrate, consequently blocking access of both substrates to the active sites. The achieved results suggest the design of new peptide sequences having a higher relative affinity to binding sites of this enzyme and an enhancement of their hypocholesterolemic properties.

Characterization of an Elastase Inhibitor Produced by Streptomyces lavendulae SMF11

  • Lee, Hyun-Sook;Jin, Wook;Kang, Sung-Gyun;Hwang, Yoon-Sook;Kho, Yung-Hee;Lee, Kye-Joon
    • Journal of Microbiology and Biotechnology
    • /
    • v.10 no.1
    • /
    • pp.81-85
    • /
    • 2000
  • An elastase inhibitor, SMFEI02, was isolated from culture broth of Streptomyces lavendulae SMF11. The inhibitor was purified by ultrafiltration followed by XAD-7 column and Dowex-1 anion-exchange chromatographies, and preparative HPLC. The molecular formula was determined to be $C_{14}H_{16}N_2O_2$ (MW244) by HRFAB-MS analysis. The inhibitor was identified to be a diketopiperazine cyclo(S-Phe-S-Pro) by the optical rotation value and MNR spectral data, and showed inhibitory activities for trypsin, chymotrypsin, cathepsin B, and papain as well as elastase with the Ki values ranging from 1.78mM to $2.86{\;}\mu\textrm{m}$. The inhibition showed a competitive mode for elastase, chymotrypsin, and cathepsin B, whereas it showed a noncompetitive mode for trypsin and papain.

  • PDF

Rosmarinic Acid as a Tyrosinase Inhibitors from Salvia miltiorrhiza

  • Kang, Hye-Sook;Kim, Hyung-Rak;Byun, Dae-Seok;Park, Hye-Jin;Choi, Jae-Sue
    • Natural Product Sciences
    • /
    • v.10 no.2
    • /
    • pp.80-84
    • /
    • 2004
  • Rosmarinic acid and its methyl ester, isolated from the ethyl acetate soluble fraction of the methanolic extract of Salvia miltiorrhiza Bunge (Labiatae), were found to inhibit the oxidation of L-tyrosine catalyzed by mushroom tyrosinase with the $IC_{50}$ values of 16.8 and $21.5\;{\mu}M$, respectively. It was comparable with kojic acid, a well-known tyrosinase inhibitor, with an $IC_{50}$ of $22.4\;{\mu}M$. The inhibitory kinetics analyzed by the Lineweaver-Burk plots, were found rosmarinic acid and its methyl ester to be competitive inhibitors with $K_i\;of\;2.4{\times}10^{-5}\;and\;1.5{\times}10^{-5}\;M$, respectively.

Isoliquiritigenin : A Competitive Tyrosinase Inhibitor from the Heartwood of Dalbergia odorifera

  • Kang, Tai-Hyun;Tian, Yu-Hua;Kim, Youn-Chul
    • Biomolecules & Therapeutics
    • /
    • v.13 no.1
    • /
    • pp.32-34
    • /
    • 2005
  • Effect of isoliquiritigenin isolated from the heartwood of Dalbergia odorifera T. Chen (Leguminosae) on mushroom tyrosinase activity was investigated in vitro using L-tyrosine and L-3, 4-dihydroxyphenylalanine (L-DOPA) as the substrates. When L-tyrosine was used as a substrate, both isoliquiritigenin and kojic acid, a positive control, inhibited tyrosinase activity in a concentration-dependent manner. IC$_{50}$ values of isoliquiritigenin and kojic acid were 61.4 and 52.2 ${\muM}$, respectively. However, isoliquiritigenin showed week inhibitory effect on the oxidation of L-DOPA by tyrosinase with inhibition ratio of 9.1 ${\pm}$ 7.1% at 100 ${\muM}$. It is also suggested that 3-unsubstituted and 4-hydroxyl phenyl group in isoliquiritigenin plays an important role on the inhibition of tyrosinase activity when L-tyrosine was used as a substrate. Analysis of Lineweaver-Burk plot showed that isoliquiritigenin acts as a competitive inhibitor in case of L-tyrosine as a substrate.

Inhibition of protein tyrosine phosphatase non-receptor type 2 by PTP inhibitor XIX: Its role as a multiphosphatase inhibitor

  • Le, Hien Thi Thu;Cho, Young-Chang;Cho, Sayeon
    • BMB Reports
    • /
    • v.50 no.6
    • /
    • pp.329-334
    • /
    • 2017
  • Protein tyrosine phosphatases (PTPs) play crucial roles in signal transduction and their functional alteration has been detected in many diseases. PTP inhibitors have been developed as therapeutic drugs for diseases that are related to the activity of PTPs. In this study, PTP inhibitor XIX, an inhibitor of CD45 and PTEN, was investigated whether it inhibits other PTPs. Protein tyrosine phosphatase non-receptor type 2 (PTPN2) was selectively inhibited by the inhibitor in a competitive manner. Drug affinity responsive target stability (DARTS) analysis showed that the inhibitor induces conformational changes in PTPN2. Phosphorylation levels of signal transducer and activator of transcription 3 (STAT3) at Tyr-705, a crucial site for STAT3 activation and target site of PTPN2, decreased upon exposure to the inhibitor. Our results suggest that PTP inhibitor XIX might be considered as an effective regulator of PTPN2 for treating diseases related to PTPN2.