Identification of the Critical Role of Tyr-194 in the Catalytic Activity of a Novel N-Acyl-Homoserine Lactonase from Marine Bacillus cereus Strain Y2

2006 ◽  
Vol 53 (4) ◽  
pp. 346-350 ◽  
Author(s):  
X. Lu ◽  
Y. Yuan ◽  
X.-L. Xue ◽  
G.-P. Zhang ◽  
S.-N. Zhou
Keyword(s):  
Catalytic Activity ◽  
Bacillus Cereus ◽  
Critical Role

scholarly journals Core–shell Au@AuAg nano-peanuts for the catalytic reduction of 4-nitrophenol: critical role of hollow interior and broken shell structure

2020 ◽  
Vol 2 (10) ◽  
pp. 4841-4852
Author(s):  
Varsha Thambi ◽  
Abhay Raj Singh Gautam ◽  
Saumyakanti Khatua
Keyword(s):  
Catalytic Activity ◽  
Shell Structure ◽  
Catalytic Reduction ◽  
Critical Role ◽  
Core Shell ◽  
Hole Size ◽  
Hollow Interior

We report the synthesis and enhanced catalytic activity of broken-shell nano-peanuts with variable hole size.

Abstract 4339: Critical role of Dnmt3b catalytic activity in prevention of oncogene-induced leukemias and lymphomas

2019 ◽  
Author(s):  
Katarina Lopusna ◽  
Pawel Nowialis ◽  
Staci L. Haney ◽  
Ajay Abraham ◽  
Jana Opavska ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Critical Role ◽  
Leukemias And Lymphomas

Effect of matrix metallopeptidase 13 (MMP13) on multiple myeloma (MM) cells, osteoclast (OCL) activity, and bone resorption.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 8099-8099
Author(s):  
Jing Fu ◽  
Shirong Li ◽  
Rentian Feng ◽  
Mei Hua Jin ◽  
Farideh Sabeh ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Bone Resorption ◽  
Bone Disease ◽  
Critical Role ◽  
Site Directed Mutagenesis ◽  
Hek293 Cells ◽  
Bone Lesions ◽  
Lytic Lesions

8099 Background: MM cells produce OCL-activating factors that induce excessive bone resorption resulting in lytic lesions. The role of MMPs in invasion/progression of solid tumors is well-known, but its function in MM has not been well elucidated. Our group has shown that MMP13 is highly expressed in primary MM cells and in sera of MM patients. Levels of MMP13 significantly correlate with the extent of bone disease. MMP13 is induced by IL-6 via AP-1 activation in MM cells and enhances fusion of OCL precursors resulting in excessive bone resorption. OCL formation using MNCs of mmp-13-/- mice resulted in a fusion defect, significantly decreased OCL size and activity, which could be reversed by exogenous MMP13 (ASH 2009, IMW 2011). Methods: Methods will be presented in the Results section. Results: RT-PCR and western blotting revealed that IL-6 treatment of MM cells induced MMP13 transcription (30-fold) and secretion (>1000-fold). Protein expression of the AP-1 members c-Jun and c-Fos was induced by IL-6, which correlated with MMP13 upregulation. Our data further indicate that the catalytic activity of MMP13 is not required to enhance OCL formation and bone resorption. To prove this, we generated the MMP13 activity-dead mutation MMP13-E223A construct by site-directed mutagenesis PCR-based cloning. The mutated protein was overexpressed in HEK293 cells and purified from the supernatant to confirm whether loss of catalytic activity blocks MMP13 function. To further investigate the in vivo role of MMP13 in MM bone disease, MMP13 expression was knocked down (KD) in murine 5TGM1-MM cells by pKLO. 1 puro lentiviral infection containing sh-RNA targeting mouse MMP13 sequence. MMP13-KD 5TGM1-MM cells or WT-5TGM1-MM cells were intratibially injected into RAG2-/- mice. Development of lytic bone lesions are monitored by micro-QCT and data will be available at the time of presentation. Conclusions: Our data suggest that MMP13, secreted by MM cells, plays a critical role in the development of lytic lesions. Targeting MMP13 represents a promising approach to treat or to prevent bone disease in MM.

scholarly journals Structural Insight into the Critical Role of the N-Terminal Region in the Catalytic Activity of Dual-Specificity Phosphatase 26

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162115 ◽  
Author(s):  
Eun-Young Won ◽  
Sang-Ok Lee ◽  
Dong-Hwa Lee ◽  
Daeyoup Lee ◽  
Kwang-Hee Bae ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Critical Role ◽  
Terminal Region ◽  
Dual Specificity Phosphatase ◽  
Dual Specificity ◽  
Structural Insight ◽  
Insight Into

Abstract 4339: Critical role of Dnmt3b catalytic activity in prevention of oncogene-induced leukemias and lymphomas

2019 ◽  
Author(s):  
Katarina Lopusna ◽  
Pawel Nowialis ◽  
Staci L. Haney ◽  
Ajay Abraham ◽  
Jana Opavska ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Critical Role ◽  
Leukemias And Lymphomas

Ambient electrohydrogenation of N2 for NH3 synthesis on non-metal boron phosphide nanoparticles: the critical role of P in boosting the catalytic activity

2019 ◽  
Vol 7 (27) ◽  
pp. 16117-16121 ◽  
Author(s):  
Xiaojuan Zhu ◽  
Tongwei Wu ◽  
Lei Ji ◽  
Chengbo Li ◽  
Ting Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Critical Role ◽  
Reduction Reaction ◽  
Reversible Hydrogen Electrode ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Boron Phosphide

As a non-metal electrocatalyst for the N2 reduction reaction, boron phosphide nanoparticles offer a high NH3 yield of 26.42 μg h−1 mgcat.−1 and a high faradaic efficiency of 12.7% at –0.60 V vs. the reversible hydrogen electrode in 0.1 M HCl.

scholarly journals The activity of the dinuclear cobalt-β-lactamase from Bacillus cereus in catalysing the hydrolysis of β-lactams

2006 ◽  
Vol 401 (1) ◽  
pp. 197-203 ◽  
Author(s):  
Adriana Badarau ◽  
Christian Damblon ◽  
Michael I. Page
Keyword(s):  
Catalytic Activity ◽  
Bacillus Cereus ◽  
Metal Ion ◽  
Active Form ◽  
Metal Ion Binding ◽  
Deprotonated Form ◽  
Efficient Catalyst ◽  
Zinc Enzymes ◽  
Hydrolysis Of

Metallo-β-lactamases are native zinc enzymes that catalyse the hydrolysis of β-lactam antibiotics, but are also able to function with cobalt(II) and require one or two metal-ions for catalytic activity. The hydrolysis of cefoxitin, cephaloridine and benzylpenicillin catalysed by CoBcII (cobalt-substituted β-lactamase from Bacillus cereus) has been studied at different pHs and metal-ion concentrations. An enzyme group of pKa 6.52±0.1 is found to be required in its deprotonated form for metal-ion binding and catalysis. The species that results from the loss of one cobalt ion from the enzyme has no significant catalytic activity and is thought to be the mononuclear CoBcII. It appears that dinuclear CoBcII is the active form of the enzyme necessary for turnover, while the mononuclear CoBcII is only involved in substrate binding. The cobalt-substituted enzyme is a more efficient catalyst than the native enzyme for the hydrolysis of some β-lactam antibiotics suggesting that the role of the metal-ion is predominantly to provide the nucleophilic hydroxide, rather than to act as a Lewis acid to polarize the carbonyl group and stabilize the oxyanion tetrahedral intermediate.

The Role of the SLP in Autism Spectrum Disorder Screening and Assessment

2008 ◽  
Vol 15 (2) ◽  
pp. 50-59 ◽  
Author(s):  
Amy Philofsky
Keyword(s):  
Language Development ◽  
Critical Role ◽  
Children With Autism ◽  
Autism Spectrum ◽  
Children With Asd ◽  
Prevalence Estimates ◽  
Notable Increase ◽  
Screening Assessment ◽  
Critical Components

AbstractRecent prevalence estimates for autism have been alarming as a function of the notable increase. Speech-language pathologists play a critical role in screening, assessment and intervention for children with autism. This article reviews signs that may be indicative of autism at different stages of language development, and discusses the importance of several psychometric properties—sensitivity and specificity—in utilizing screening measures for children with autism. Critical components of assessment for children with autism are reviewed. This article concludes with examples of intervention targets for children with ASD at various levels of language development.

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