Somatostatin analogue octreotide increases IDE expression and secretion.

<p>(A) WB (left panel) and densitometric analysis of IDE (right panel) after 24 hrs incubation with the indicated concentrations of octreotide. (B) ELISA analysis on BV-2 medium after octreotide incubation reveals that the sst analogue induces IDE secretion. In every case, the results presented are the means ± ES of four independent experiments in triplicate. * P<0.05, oneway ANOVA, followed by Tukey's test, n = 12.</p

Values of the second-order rate constant for peroxynitrite isomerization by ferric heme-proteins.

a<p>pH 7.4 and 20°C. Present study.</p>b<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi7" target="_blank">[32]</a>.</p>c<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Coppola1" target="_blank">[31]</a>.</p>d<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Herold2" target="_blank">[22]</a>.</p>e<p>pH 7.5 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Herold4" target="_blank">[24]</a>.</p>f<p>pH 7.5 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Herold2" target="_blank">[22]</a>.</p>g<p>pH 7.2 and 22°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi4" target="_blank">[28]</a>.</p>h<p>pH 7.0 and 20°C. Cardiolipin was 1.6×10^–4 M. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi5" target="_blank">[29]</a>.</p

Values of the second-order rate constant for peroxynitrite isomerization by ferric heme-proteins.

a<p>pH 7.4 and 20°C. Present study.</p>b<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi7" target="_blank">[32]</a>.</p>c<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Coppola1" target="_blank">[31]</a>.</p>d<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Herold2" target="_blank">[22]</a>.</p>e<p>pH 7.5 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Herold4" target="_blank">[24]</a>.</p>f<p>pH 7.5 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Herold2" target="_blank">[22]</a>.</p>g<p>pH 7.2 and 22°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi4" target="_blank">[28]</a>.</p>h<p>pH 7.0 and 20°C. Cardiolipin was 1.6×10^–4 M. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi5" target="_blank">[29]</a>.</p

Values of the second-order rate constant for the nitrite-reductase activity of ferrous heme-proteins.

a<p>pH 7.0; unknown temperature <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Sturms1" target="_blank">[42]</a>.</p>b<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Tiso2" target="_blank">[45]</a>.</p>c<p>CysE20Ser mutant. pH 7.4 and 20°C. Present study.</p>d<p>pH 7.6 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Helbo1" target="_blank">[49]</a>.</p>e<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Tiso1" target="_blank">[43]</a>.</p>f<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Huang1" target="_blank">[37]</a>.</p>g<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Tiso1" target="_blank">[43]</a>.</p>h<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Petersen1" target="_blank">[40]</a>.</p>i<p>pH 7.0 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Li1" target="_blank">[44]</a>.</p>j<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Tiso1" target="_blank">[43]</a>. In “Human neuroglobin CysCD4-CysD5”, the CysCD4 and CysD5 residues form an intramolecular disulphide bond.</p>k<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Tiso1" target="_blank">[43]</a>. In “Human neuroglobin CysCD4/CysD5”, the CysCD4 and CysD5 residues do not form the intramolecular disulphide bond.</p>l<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Tiso1" target="_blank">[43]</a>.</p>m<p>pH 7.4 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi8" target="_blank">[46]</a>.</p>n<p>pH 7.4 and 25°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Li1" target="_blank">[44]</a>.</p

Somatostatin regulates IDE activity enhancing IDE-dependent Aβ degradation.

<p>(A) BV-2 cells transfected with a specific IDE siRNA pool show reduced levels of IDE protein, compared to cells transfected with a nonspecific control siRNA pool (right panel). (B) Aβ(1–40) quantification through sandwich ELISA reveals that the levels of Aβ are drastically reduced in the presence of IDE steady level (grey columns) compared to IDE-silencing samples (white columns). The results presented are the means ± ES of three independent experiments in triplicate. P<0.05, one-way ANOVA, followed by Tukey's test, n = 9. *Significantly different from internal control. ⁺Significantly different from silenced sample in the absence of somatostatin. ^×Significantly different from not-silenced sample in the absence of somatostatin.</p

Ma-Pgb* fold.

<p>(Panel A) The secondary structure elements are labeled A–H’. The 20 <i>N</i>-terminal residues and the extended CE and FG loops that seal the heme pocket and prevent the access of small ligands to the heme distal cavity are in orange. The pre-A Z-helix is in green. The heme (red) is displayed edge on. The proximal HisF8 residue is shown on the left hand side of the heme. The picture includes the mutated SerE20 residue, located at the <i>C</i>-terminus of the E-helix. The HisF8 and SerE20 side chains and residues building up the heme distal pocket are drawn as skeletal models (C atoms yellow, N atoms blue, and O atoms red) and labeled. (Panel B) Mono views of “tunnel 1” (top) and “tunnel 2” (bottom) access sites in Ma-Pgb*. Helices flanking the tunnel entries are labelled. The heme group (seen through the tunnel apertures) is shown in red. The protein is correctly oriented in both images, to bring each tunnel in the direction of sight. The images are rotated by 90°. The pictures have been drawn by UCSF - Chimera <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Pettersen1" target="_blank">[55]</a>. For details, see ref. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Nardini1" target="_blank">[11]</a>.</p

Dependence of <i>k</i>_obs1 (panel A) and <i>k</i>_obs2 (panel B) on the NO₂^– concentration for the Ma-Pgb*-Fe(II) reductase activity, at pH 7.4 and 20°C.

<p>The analysis of data according to Eqs 2 and 3 allowed the determination of the following values of <i>k</i>_app1 = 9.6±0.2 M^–1 s^–1 and <i>k</i>_app2 = 1.2±0.1 M^–1 s^–1. Where not shown, the standard deviation is smaller than the symbol. For details, see text.</p

Values of kinetic parameters for Ma-Pgb*-Fe reactivity.

a<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Abbruzzetti1" target="_blank">[15]</a>.</p>b<p>pH 7.2 and 22°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ascenzi1" target="_blank">[16]</a>.</p>c<p>pH 7.4 and 20°C. Present study.</p>d<p>pH 7.0 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Ciaccio1" target="_blank">[18]</a>.</p>e<p>pH 9.2 and 20°C. From <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095391#pone.0095391-Pesce4" target="_blank">[17]</a>.</p

Dependence of <i>h</i> on the Ma-Pgb*-Fe(III) and Ma-Pgb*-Fe(III)-azide concentration (open and filled triangles, respectively) for the peroxynitrite isomerization, at pH 7.4 and 20°C.

<p>The continuous line was calculated according to Eq. 5 with <i>h</i>_app = 3.8×10⁴ M^–1 s⁻¹ and <i>k</i>₀ = 2.8×10^–1 s⁻¹. The average value of <i>h</i>₀ obtained in the presence of Ma-Pgb*-Fe(III)-azide (filled triangles) is 2.7×10^–1 s⁻¹. The peroxynitrite concentration was 2.5×10^–4 M. The azide concentration was 1.0×10^–1 M. Where not shown, the standard deviation is smaller than the symbol. For details, see text.</p

pH dependence of <i>k</i>_cat (o), <i>k</i>₂ (x), and <i>k</i>₃ (*) (panel A), of <i>K</i>_m (o) and <i>K</i>_s (x) (panel B), and of <i>k</i>_cat/<i>K</i>_m (o) and <i>k</i>₂/<i>K</i>_s (x) (panel C) for the PSA-catalyzed hydrolysis of Mu-HSSKLQ-AMC.

<p>The continuous lines have been obtained by non-linear least-squares fitting of data according to Eqs. 7–12 with parameters reported in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102470#pone-0102470-g006" target="_blank">Figure 6</a>. The temperature was 37.0°C</p