scholarly journals Involvement of the Hydroperoxy Group in the Irreversible Inhibition of Leukocyte-Type 12-Lipoxygenase by Monoterpene Glycosides Contained in the Qing Shan Lu Shui Tea

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 304
Author(s):  
Yuki Kawakami ◽  
Akemi Otsuki ◽  
Yoshiko Mori ◽  
Keita Kanzaki ◽  
Toshiko Suzuki-Yamamoto ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Inhibitory Effect ◽  
Irreversible Inhibition ◽  
Backbone Structure ◽  
12 Lipoxygenase ◽  
Chemical Evidence ◽  
Monoterpene Glycosides

We have previously found two novel monoterpene glycosides, liguroside A and liguroside B, with an inhibitory effect on the catalytic activity of the enzyme leukocyte-type 12-lipoxygenase in the Qing Shan Lu Shui tea. Here, two new monoterpene glycosides, liguroside C and liguroside D which inhibit this enzyme, were isolated from the same tea. The spectral and chemical evidence characterized the structures of these compounds as (5E)-7-hydroperoxy-3,7-dimethyl-1,5-octadienyl-3-O-(α-l-rhamnopyranosyl)-(1′′→3′)-(4′′′-O-trans-p-coumaroyl)-β-d-glucopyranoside and (2E)-6-hydroxy-3,7-dimethyl-2,7-octadienyl-3-O-(α-l-rhamnopyranosyl)-(1′′→3′)-(4′′′-O-trans-p-coumaroyl)-β-d-glucopyranoside, respectively. These ligurosides, which irreversibly inhibited leukocyte-type 12-lipoxygenase, have a hydroperoxy group in the monoterpene moiety. Additionally, monoterpene glycosides had the same backbone structure but did not have a hydroperoxy group, such as kudingoside A and lipedoside B-III, contained in the tea did not inhibit the enzyme. When a hydroperoxy group in liguroside A was reduced by using triphenylphosphine, the resultant compound, kudingoside B, showed a lower inhibitory effect on the enzyme. These results strongly suggest the involvement of the hydroperoxy group in the irreversible inhibition of the catalytic activity of leukocyte-type 12-lipoxygenase by the monoterpene glycosides contained in the Qing Shan Lu Shui tea.

scholarly journals Protein kinase C in rod outer segments: effects of phosphorylation of the phosphodiesterase inhibitory subunit

1996 ◽  
Vol 317 (1) ◽  
pp. 291-295 ◽  
Author(s):  
Igor P. UDOVICHENKO ◽  
Jess CUNNICK ◽  
Karen GONZALEZ ◽  
Alexander YAKHNIN ◽  
Dolores J. TAKEMOTO
Keyword(s):  
Protein Kinase C ◽  
Catalytic Activity ◽  
Protein Kinase ◽  
Direct Interaction ◽  
Inhibitory Effect ◽  
Rod Outer Segments ◽  
Visual Transduction ◽  
Gtp Hydrolysis ◽  
Outer Segments ◽  
Kinase C

The inhibitory subunit (PDEγ) of the cGMP phosphodiesterase (PDEαβγ2) in rod outer segments (ROS) realizes its regulatory role in phototransduction by inhibition of PDEαβ catalytic activity. The photoreceptor G-protein, transducin, serves as a transducer from the receptor (rhodopsin) to the effector (PDE) and eliminates the inhibitory effect of PDEγ by direct interaction with PDEγ. Our previous study [Udovichenko, Cunnick, Gonzalez and Takemoto (1994) J. Biol. Chem. 269, 9850–9856] has shown that PDEγ is a substrate for protein kinase C (PKC) from ROS and that phosphorylation by PKC increases the ability of PDEγ to inhibit PDEαβ catalytic activity. Here we report that transducin is less effective in activation of PDEαβ(γp)2 (a complex of PDEαβ with phosphorylated PDEγ, PDEγp) than PDEαβγ2. PDEγp also increases the rate constant of GTP hydrolysis of transducin (from 0.16 s-1 for non-phosphorylated PDEγ to 0.21 s-1 for PDEγp). These data suggest that phosphorylation of the inhibitory subunit of PDE by PKC may regulate the visual transduction cascade by decreasing the photoresponse.

scholarly journals The effect of the γ-subunit of the cyclic GMP phosphodiesterase of bovine and frog (Rana catesbiana) retinal rod outer segments on the kinetic parameters of the enzyme

1990 ◽  
Vol 265 (3) ◽  
pp. 655-658 ◽  
Author(s):  
M M Whalen ◽  
M W Bitensky ◽  
D J Takemoto
Keyword(s):  
Catalytic Activity ◽  
Cyclic Gmp ◽  
Active Sites ◽  
Outer Segment ◽  
Maximal Activity ◽  
Inhibitory Effect ◽  
Gamma Subunit ◽  
Rod Outer Segment ◽  
Gamma Subunits ◽  
Alpha Beta

Rod-outer-segment cyclic GMP phosphodiesterase (PDE) (subunit composition alpha beta gamma 2) contains catalytic activity in alpha beta. The gamma-subunits are inhibitors. Removal of the gamma-subunits increases Vmax. without affecting the Km. The inhibitory effect of a single gamma-subunit (alpha beta gamma) on the Vmax. of alpha beta is much greater in bovine than in frog (Rana catesbiana) PDE. Bovine PDE in the alpha beta gamma 2 state has a Vmax. that is 2.6 +/- 0.4% of the Vmax. of alpha beta. The removal of one gamma-subunit to give alpha beta gamma results in a Vmax. 5.2 +/- 1% of that for maximal activity. Frog alpha beta gamma 2 has a Vmax. 10.8 +/- 2%, and alpha beta gamma has a Vmax. 50 +/- 18%, of the Vmax. of alpha beta. These data suggest that a single gamma-subunit can inhibit the catalytic activity of active sites on both alpha- and beta-subunits in bovine, but not in frog, rod-outer-segment PDE.

Functional Analysis of a Peptide Sequence (Thr323 - Cys337) In ADAMTS13 Disintegrin-Like Domain Revealed Two Discontinuous Sequences Involved In the Interaction with VWF

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2200-2200
Author(s):  
Atsuko Igari ◽  
Takanori Moriki ◽  
Terumichi Nakagawa ◽  
Yusuke Yamaguchi ◽  
Mitsuru Murata
Keyword(s):  
Amino Acids ◽  
Catalytic Activity ◽  
Synthetic Peptides ◽  
Inhibitory Effect ◽  
Peptide Sequence ◽  
Recent Analysis ◽  
Inhibitory Effects ◽  
Amino Terminal ◽  
Terminal Amino ◽  
Carboxyl Terminal

Abstract Abstract 2200 ADAMTS13 specifically cleaves multimeric von Willebrand factor (VWF) into smaller molecules to reduce its high reactivity with platelets. The disintegrin-like (D) domain, adjacent to the catalytic domain of ADAMTS13, plays an important role in the process of VWF cleavage. In this study, we aimed to elucidate critical peptide sequences in D-domain involved in the interaction with VWF. A series of partially overlapping peptide sequences, approximately 20 amino acids in length, covering the D-domain, were synthesized and the inhibitory effects on the catalytic activity of plasma ADAMTS13 was examined using FRETS-VWF73 assay. Consequently, some synthetic peptides were selected and the minimal length necessary for the inhibitory effect was determined as TFAREHLDMCQALSC (peptide323-337). Removal of the amino-terminal threonine diminished the inhibitory effect moderately, although deletion of the carboxyl-terminal cysteine abolished it completely. According to the amino acids alignment of ADAMTS family, this peptide sequence is not conserved, highlighting the specific role in the interaction with its substrate. From the recent analysis of crystal structure, amino-terminal half of the peptide323-337, TFAREHL (323-329), was disordered and designated as the variable (V) loop, which creates one of VWF-binding exosites (Akiyama, et al. Proc Natl Acad Sci USA. 2009; 106:19274-9). We hypothesized that the amino-terminal amino acids of the peptide323-337 contribute to VWF binding, whereas the carboxyl-terminal amino acids allow the structural stability of the peptide conformation. To evaluate the effect of carboxyl-terminal cysteine at 337, other synthetic peptides with alanine, serine, glycine or phenylalanine instead of the cysteine (C337A, C337S, C337G, or C337F) were tested about their inhibitory effects on the catalytic activity. Interestingly, C337A, C337S, C337G peptides exhibited slightly weaker inhibitory effects on VWF73 catalysis, although C337F peptide showed stronger inhibition than wild-type sequence, suggesting that the residue 337 regulates the characteristics of the peptide323-337. From the results of peptide screening, the amino- and carboxyl-terminal amino acids of the peptide323-337, TFAREHLDMCQALSC, likely play key roles in the inhibitory effects; therefore, the middle part of the sequence, HLDMC, was replaced by 5 alanines (AAAAA) or reversed sequence CMDLH. Surprisingly, the converted peptides still retained the equivalent level of inhibitory effects, indicating both sides of the amino- and carboxyl-terminal amino acids were especially significant in the interaction with VWF. In conclusion, we characterized the peptide sequence, TFAREHLDMCQALSC (323-337), in D-domain. The peptide clearly inhibited the cleavage of VWF73 and the both sides of amino- and carboxyl-terminal amino acids seemed especially important. The peptide sequence is supposed to bind to VWF for the precise cleavage in the process of proteolysis. By modifying this peptide sequence, such variant ADAMTS13 as gain-of-function recombinants might be developed, leading to an alternative anti-thrombotic drug. Disclosures: No relevant conflicts of interest to declare.

Identification of disulfide isomerase ERp57 as a target for small molecule cardioprotective agents

RSC Advances ◽  
2015 ◽  
Vol 5 (91) ◽  
pp. 74605-74610 ◽  
Author(s):  
Guozhen Cui ◽  
Luchen Shan ◽  
Ivan Keung Chu ◽  
Guohui Li ◽  
George Pak Heng Leung ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Catalytic Activity ◽  
Protective Effect ◽  
Small Molecule ◽  
Inhibitory Effect ◽  
Disulfide Isomerase ◽  
Specific Target ◽  
Proteomic Approach ◽  
Potent Inhibitory Effect

Compound BAA exhibited protective effect against oxidative stress-induced cells injury in H9c2 cardiomyoblast. Chemical proteomic approach identified ERp57 as the specific target for BAA. Furthermore, BAA displayed potent inhibitory effect on the catalytic activity of ERp57.

scholarly journals Human xylosyltransferase I: functional and biochemical characterization of cysteine residues required for enzymic activity

2005 ◽  
Vol 386 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Sandra MÜLLER ◽  
Manuela SCHÖTTLER ◽  
Sylvia SCHÖN ◽  
Christian PRANTE ◽  
Thomas BRINKMANN ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Biochemical Characterization ◽  
Active Form ◽  
Inhibitory Effect ◽  
Enzymic Activity ◽  
Site Directed Mutagenesis ◽  
Cysteine Residues ◽  
Thiol Groups ◽  
Wild Type ◽  
Free Thiol

XT-I (xylosyltransferase I) is the initial enzyme in the post-translational biosynthesis of glycosaminoglycan chains in proteoglycans. To gain insight into the structure–function relationship of the enzyme, a soluble active form of human XT-I was expressed in High Five insect cells with an apparent molecular mass of 90 kDa. Analysis of the electrophoretic mobility of the protein under non-reducing and reducing conditions indicated that soluble XT-I does not form homodimers through disulphide bridges. In addition, the role of the cysteine residues was investigated by site-directed mutagenesis combined with chemical modifications of XT-I by N-phenylmaleimide. Replacement of Cys471 or Cys574 with alanine led to a complete loss of catalytic activity, indicating the necessity of these residues for maintaining an active conformation of soluble recombinant XT-I by forming disulphide bonds. On the other hand, N-phenylmaleimide treatment showed no effect on wild-type XT-I but strongly inactivated the cysteine mutants in a dose-dependant manner, indicating that seven intramolecular disulphide bridges are formed in wild-type XT-I. The inhibitory effect of UDP on the XT-I activity of C561A (Cys561→Ala) mutant enzyme was significantly reduced compared with all other tested cysteine mutants. In addition, we tested for binding to UDP-agarose beads. The inactive mutants revealed no significantly different nucleotide-binding properties. Our study demonstrates that recombinant XT-I is organized as a monomer with no free thiol groups and strongly suggests that the catalytic activity does not depend on the presence of free thiol groups, furthermore, we identified five cysteine residues which are critical for enzyme activity.

A “light-on” colorimetric assay for anion detection using the inhibitory effect of anions on the catalytic activity of metal nanoparticles for the degradation of methyl orange

The Analyst ◽  
2014 ◽  
Vol 139 (23) ◽  
pp. 6122-6125 ◽  
Author(s):  
Lixia Lu ◽  
Fan Yang ◽  
Xiurong Yang
Keyword(s):  
Catalytic Activity ◽  
Methyl Orange ◽  
Metal Nanoparticles ◽  
Colorimetric Assay ◽  
Colorimetric Method ◽  
Inhibitory Effect ◽  
Anion Detection ◽  
Degradation Of Methyl Orange

A “light-on” colorimetric method for anion detection using the catalytic ability of metal nanoparticles for methyl orange (MO) degradation was developed.

scholarly journals Evidence for active interactions between microfilaments and microtubules in myxomycete flagellates.

1989 ◽  
Vol 108 (5) ◽  
pp. 1727-1735 ◽  
Author(s):  
T Q Uyeda ◽  
M Furuya
Keyword(s):  
Physarum Polycephalum ◽  
Inhibitory Effect ◽  
Subsequent Treatment ◽  
Apparent Displacement ◽  
Microtubular Cytoskeleton ◽  
Backbone Structure ◽  
Gamma S ◽  
Uniform Polarity

We have previously observed the apparent displacement of microfilaments over microtubules in the backbone structure of permeabilized flagellates of Physarum polycephalum upon addition of ATP (Uyeda, T. Q. P., and M. Furuya. 1987. Protoplasma. 140:190-192). We now report that disrupting the microtubular cytoskeleton by treatment with 0.2 mM Ca2+ for 3-30 s inhibits the movement of the microfilaments induced by subsequent treatment with 1 mM Mg-ATP and 10 mM EGTA. Stabilization of microtubules by pretreatment with 50 microM taxol retarded both the disintegrative effect of Ca2+ on the microtubules and the inhibitory effect of Ca2+ on the subsequent, ATP-induced movement of the microfilaments. These results suggest that the movement of the microfilaments depends on the integrity of the microtubular cytoskeleton. EM observation showed that the backbone structure in control permeabilized flagellates consists of two arrays of microtubules closely aligned with bundles of microfilaments of uniform polarity. The microtubular arrays after ATP treatment were no longer associated with microfilaments, yet their alignment was not affected by the ATP treatment. These results imply that the ATP treatment induces reciprocal sliding between the microfilaments and the microtubules, rather than between the microfilaments themselves or between the microtubules themselves. While sliding was best stimulated by ATP, the movement was partially induced by GTP or ATP gamma S, but not by ADP or adenylyl-imidodiphosphate (AMP-PNP). AMP-PNP added in excess to ATP, 50 microM vanadate, or 2 mM erythro-9-[3-(2-hydroxynonyl)]adenine (EHNA) inhibited the sliding. Thus, the pharmacological characteristics of this motility were partly similar to, although not the same as, those of the known microtubule-dependent motilities.

scholarly journals Centrin 3 is an inhibitor of centrosomal Mps1 and antagonizes centrin 2 function

2015 ◽  
Vol 26 (21) ◽  
pp. 3741-3753 ◽  
Author(s):  
Dwitiya B. Sawant ◽  
Shubhra Majumder ◽  
Jennifer L. Perkins ◽  
Ching-Hui Yang ◽  
Patrick A. Eyers ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Protein Kinase ◽  
Calcium Binding ◽  
Biological Effects ◽  
Inhibitory Effect ◽  
Calcium Binding Proteins ◽  
Centrosome Duplication ◽  
Phosphorylation Sites ◽  
Cellular Functions

Centrins are a family of small, calcium-binding proteins with diverse cellular functions that play an important role in centrosome biology. We previously identified centrin 2 and centrin 3 (Cetn2 and Cetn3) as substrates of the protein kinase Mps1. However, although Mps1 phosphorylation sites control the function of Cetn2 in centriole assembly and promote centriole overproduction, Cetn2 and Cetn3 are not functionally interchangeable, and we show here that Cetn3 is both a biochemical inhibitor of Mps1 catalytic activity and a biological inhibitor of centrosome duplication. In vitro, Cetn3 inhibits Mps1 autophosphorylation at Thr-676, a known site of T-loop autoactivation, and interferes with Mps1-dependent phosphorylation of Cetn2. The cellular overexpression of Cetn3 attenuates the incorporation of Cetn2 into centrioles and centrosome reduplication, whereas depletion of Cetn3 generates extra centrioles. Finally, overexpression of Cetn3 reduces Mps1 Thr-676 phosphorylation at centrosomes, and mimicking Mps1-dependent phosphorylation of Cetn2 bypasses the inhibitory effect of Cetn3, suggesting that the biological effects of Cetn3 are due to the inhibition of Mps1 function at centrosomes.

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