Single Gold Nanoparticle-driven Heme Cofactor Nanozyme as Unprecedented Oxidase Mimetic

2021 ◽  
Author(s):  
Yan Liu ◽  
Zhen Chen ◽  
Zhifang Shao ◽  
Rong Guo
Keyword(s):  
Catalytic Activity ◽  
Gold Nanoparticle ◽  
Heme Enzymes ◽  
Biomimetic Chemistry ◽  
Catalytic Function ◽  
Heme Cofactor

The catalytic diversity of heme enzymes is a perpetuating pursuit for biomimetic chemistry, but heme nanozymes exhibit catalytic activity only reminiscent of peroxidases. Miraculously, the oxidase-like catalytic function of heme...

Beyond the Roles in Biomimetic Chemistry: An Insight into the Intrinsic Catalytic Activity of an Enzyme for Tumor-Selective Phototheranostics

ACS Nano ◽  
2018 ◽  
Vol 12 (12) ◽  
pp. 12169-12180 ◽  
Author(s):  
Weitao Yang ◽  
Xiudong Shi ◽  
Yuxin Shi ◽  
Defan Yao ◽  
Shizhen Chen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Biomimetic Chemistry ◽  
Insight Into ◽  
Tumor Selective

Catalytic oxidation of diorganosilanes to 1,1,3,3-tetraorganodisiloxanes with gold nanoparticle assembly at the water–chloroform interface

2019 ◽  
Vol 43 (2) ◽  
pp. 813-819 ◽  
Author(s):  
Ravi Shankar ◽  
Asmita Sharma ◽  
Bhawana Jangir ◽  
Manchal Chaudhary ◽  
Gabriele Kociok-Köhn
Keyword(s):  
Catalytic Activity ◽  
Ambient Temperature ◽  
Catalytic Oxidation ◽  
Gold Nanoparticle ◽  
Photothermal Effect ◽  
Nanoparticle Assembly

The synthesis of 1,1,3,3-tetraorganodisiloxanes from the hydrolytic oxidation of diorganosilanes, RR1SiH2, using AuNPs as an interfacial catalyst is described. This study provides a manifestation of the photothermal effect in enhancing the catalytic activity at ambient temperature.

scholarly journals Laser illumination-induced dramatic catalytic activity change on Au nanospheres

2019 ◽  
Vol 10 (22) ◽  
pp. 5793-5800 ◽  
Author(s):  
Zhongju Ye ◽  
Lin Wei ◽  
Lehui Xiao ◽  
Jianfang Wang
Keyword(s):  
Catalytic Activity ◽  
Symmetry Breaking ◽  
Gold Nanoparticle ◽  
Single Particle ◽  
Catalytic Properties ◽  
Activity Change ◽  
Laser Illumination ◽  
Single Particle Level ◽  
Particle Level ◽  
First Time

In this work, the distinct catalytic properties of a single gold nanoparticle (GNP) after symmetry breaking were disclosed at the single-particle level for the first time.

scholarly journals Synthesis of Carbon Nanotubes by Plasma-Enhanced Chemical Vapor Deposition Using Fe1−xMnxO Nanoparticles as Catalysts: How Does the Catalytic Activity of Graphitization Affect the Yields and Morphology?

2019 ◽  
Vol 5 (3) ◽  
pp. 46 ◽  
Author(s):  
Takashi Yanase ◽  
Takuya Miura ◽  
Tatsuya Shiratori ◽  
Mengting Weng ◽  
Taro Nagahama ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Thermal Cvd ◽  
Catalytic Function ◽  
Yield And Quality ◽  
Synthesis Of Carbon Nanotubes

The choice of a catalyst for carbon nanotube (CNT) growth is critical to controlling the morphology and chirality of the final product. Plasma-enhanced chemical vapor deposition (PECVD) can alleviate the requirements of the catalyst, i.e., they must be active for both the decomposition of the source gas and graphitization in the conventional thermal CVD. However, it is still not well understood how the catalytic activity of the graphitization affects the yield and quality of CNTs. In this paper, we systematically investigated the influence of the catalytic activity of graphitization by tuning the composition of Fe1−xMnxO (x = 0–1) nanoparticles as catalysts. As the Mn component increased, the number of CNTs decreased because Mn has no catalytic function of the graphitization. The quality of CNTs also affected by the inclusion of the Mn component. Our study may provide useful information to develop a new catalyst for CNT growth in PECVD.

scholarly journals Negative regulation of Raf-1 by phosphorylation of serine 621.

1996 ◽  
Vol 16 (10) ◽  
pp. 5409-5418 ◽  
Author(s):  
H Mischak ◽  
T Seitz ◽  
P Janosch ◽  
M Eulitz ◽  
H Steen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Kinase Activity ◽  
Phosphorylation Site ◽  
Kinase Domain ◽  
Negative Regulation ◽  
Catalytic Function ◽  
Dependent Protein ◽  
The One

The elevation of cyclic AMP (cAMP) levels in the cell downregulates the activity of the Raf-1 kinase. It has been suggested that this effect is due to the activation of cAMP-dependent protein kinase (PKA), which can directly phosphorylate Raf-1 in vitro. In this study, we confirmed this hypothesis by coexpressing Raf-1 with the constitutively active catalytic subunit of PKA, which could fully reproduce the inhibition previously achieved by cAMP. PKA-phosphorylated Raf-1 exhibits a reduced affinity for GTP-loaded Ras as well as impaired catalytic activity. As the binding to GTP-loaded Ras induces Raf-1 activation in the cell, we examined which mechanism is required for PKA-mediated Raf-1 inhibition in vivo. A Raf-1 point mutant (RafR89L), which is unable to bind Ras, as well as the isolated Raf-1 kinase domain were still fully susceptible to inhibition by PKA, demonstrating that the phosphorylation of the Raf-1 kinase suffices for inhibition. By the use of mass spectroscopy and point mutants, PKA phosphorylation site was mapped to a single site in the Raf-1 kinase domain, serine 621. Replacement of serine 621 by alanine or cysteine or destruction of the PKA consensus motif by changing arginine 618 resulted in the loss of catalytic activity. Notably, a mutation of serine 619 to alanine did not significantly affect kinase activity or regulation by activators or PKA. Changing serine 621 to aspartic acid yielded a Raf-1 protein which, when expressed to high levels in Sf-9 insect cells, retained a very low inducible kinase activity that was resistant to PKA downregulation. The purified Raf-1 kinase domain displayed slow autophosphorylation of serine 621, which correlated with a decrease in catalytic function. The Raf-1 kinase domain activated by tyrosine phosphorylation could be downregulated by PKA. Specific removal of the phosphate residue at serine 621 reactivated the catalytic activity. These results are most consistent with a dual role of serine 621. On the one hand, serine 621 appears essential for catalytic activity; on the other hand, it serves as a phosphorylation site which confers negative regulation.

Facile preparation of tiny gold nanoparticle loaded magnetic yolk–shell carbon nanoreactors for confined catalytic reactions

2016 ◽  
Vol 40 (11) ◽  
pp. 9684-9693 ◽  
Author(s):  
Yanming Shao ◽  
Lincheng Zhou ◽  
Chao Bao ◽  
Qiong Wu ◽  
Wenling Wu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Gold Nanoparticle ◽  
Catalytic Reactions ◽  
Core Shell ◽  
One Step ◽  
Facile Preparation

Facile one-step preparation of core/shell/shell nanospheres and tiny Au loaded magnetic yolk–shell carbon nanoreactors with excellent catalytic activity.

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