Advances in Detection Methods of l-Amino Acid Oxidase Activity

Yu, Zhiliang; Wang, Yunlong; Zhou, Ning; Zhao, Minyan; Qiu, Juanping; Lin, Jianxun

doi:10.1007/s12010-014-1005-0

Cited by 7 publications

(5 citation statements)

References 66 publications

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“…Despite the prevalent application of mutagenesis technique, such as transposon mutagenesis, in mutant screening since the past decade, applying the detection method cheaply and efficiently for large-scale screening of mutants with different LAAO activities has proven challenging [ 32 ]. To date, very little is known about the regulation mechanism underlying LAAO transcription and production in marine bacteria.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, over 4,000 mutants with Rif and Km resistance were isolated and screened using Prussian blue agar assay, where only about 300 (7.5%) mutants in total were found to have altered LAAO activity. Among them, more than 95% mutants only had slight changes in LAAO activity, resulting in the difficulty for clear differentiation of mutants, which in the future could be overcome by using ferric-xylenol orange formation (Fe Ⅲ -XO) agar assay method with higher sensitivity [ 32 , 33 ] for detecting LAAO activity.…”

Section: Discussionmentioning

confidence: 99%

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Exploring Regulation Genes Involved in the Expression of L-Amino Acid Oxidase in Pseudoalteromonas sp. Rf-1

Lin

et al. 2015

PLoS ONE

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Bacterial L-amino acid oxidase (LAAO) is believed to play important biological and ecological roles in marine niches, thus attracting increasing attention to understand the regulation mechanisms underlying its production. In this study, we investigated genes involved in LAAO production in marine bacterium Pseudoalteromonas sp. Rf-1 using transposon mutagenesis. Of more than 4,000 mutants screened, 15 mutants showed significant changes in LAAO activity. Desired transposon insertion was confirmed in 12 mutants, in which disrupted genes and corresponding functionswere identified. Analysis of LAAO activity and lao gene expression revealed that GntR family transcriptional regulator, methylase, non-ribosomal peptide synthetase, TonB-dependent heme-receptor family, Na+/H+ antiporter and related arsenite permease, N-acetyltransferase GCN5, Ketol-acid reductoisomerase and SAM-dependent methytransferase, and their coding genes may be involved in either upregulation or downregulation pathway at transcriptional, posttranscriptional, translational and/or posttranslational level. The nhaD and sdmT genes were separately complemented into the corresponding mutants with abolished LAAO-activity. The complementation of either gene can restore LAAO activity and lao gene expression, demonstrating their regulatory role in LAAO biosynthesis. This study provides, for the first time, insights into the molecular mechanisms regulating LAAO production in Pseudoalteromonas sp. Rf-1, which is important to better understand biological and ecological roles of LAAO.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Exploring Regulation Genes Involved in the Expression of L-Amino Acid Oxidase in Pseudoalteromonas sp. Rf-1

Lin

et al. 2015

PLoS ONE

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“…The L-amino acid oxidase (LAAO, EC 1.4.3.2) are flavoenzymes catalyzing the stereospecific oxidative deamination of L-amino acids to produce α-keto acids, ammonia and H 2 O 2 1 2 3 . As one major snake venom (SV) component, LAAO commonly exists as homodimeric FAD-(flavin adenine dinucleotide) or FMN-(flavin mono-nucleotide) glycoprotein 4 5 6 .…”

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confidence: 99%

Akbu-LAAO exhibits potent anti-tumor activity to HepG2 cells partially through produced H2O2 via TGF-β signal pathway

Guo

Liu

Dong

et al. 2015

Sci Rep

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Previously, we characterized the biological properties of Akbu-LAAO, a novel L-amino acid oxidase from Agkistrodon blomhoffii ussurensis snake venom (SV). Current work investigated its in vitro anti-tumor activity and underlying mechanism on HepG2 cells. Akbu-LAAO inhibited HepG2 growth time and dose-dependently with an IC50 of ~38.82 μg/mL. It could induce the apoptosis of HepG2 cells. Akbu-LAAO exhibited cytotoxicity by inhibiting growth and inducing apoptosis of HepG2 as it showed no effect on its cell cycle. The inhibition of Akbu-LAAO to HepG2 growth partially relied on enzymatic-released H2O2 as catalase only partially antagonized this effect. cDNA microarray results indicated TGF-β signaling pathway was linked to the cytotoxicity of Akbu-LAAO on HepG2. TGF-β pathway related molecules CYR61, p53, GDF15, TOB1, BTG2, BMP2, BMP6, SMAD9, JUN, JUNB, LOX, CCND1, CDK6, GADD45A, CDKN1A were deregulated in HepG2 following Akbu-LAAO stimulation. The presence of catalase only slightly restored the mRNA changes induced by Akbu-LAAO for differentially expressed genes. Meanwhile, LDN-193189, a TGF-β pathway inhibitor reduced Akbu-LAAO cytotoxicity on HepG2. Collectively, we reported, for the first time, SV-LAAO showed anti-tumor cell activity via TGF-β pathway. It provides new insight of SV-LAAO exhibiting anti-tumor effect via a novel signaling pathway.

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“…Hence, LAAO is defined as toxic protein. Although LAAO showed broad applications in biosensor, biotransformation, and bleaching (Yu and Qiao 2012), its large-scale application is currently limited due to the challenge in heterologous expression derived from its toxicity to host cells (Yu et al 2014a). Hence, how the LAAO-producing organisms control and adapt to the LAAO accumulation is important, but not very clear yet.…”

Section: Introductionmentioning

confidence: 99%

Reactive oxygen species-scavenging system is involved in l-amino acid oxidase accumulation in Pseudoalteromonas sp. B3

Yang

Wang

et al. 2017

3 Biotech

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To date, the mechanisms underlying the flavoprotein l-amino acid oxidase (LAAO) accumulation in cells remain unclear. In this study, using LAAO-producer spp. as model organisms, we found that the cell biomass is negatively associated with LAAO accumulation, whereas the LAAO accumulation is positively associated with the reactive oxygen species (ROS)-scavenging capability. The expression levels of ROS-scavenging-associated genes were up-regulated with LAAO accumulation in cells, which is presumably due to the requirement for the removal of LAAO-induced ROS. Exogenous HO exposure experiment supported that the ROS-scavenging system is associated with LAAO accumulation in . All these observations indicate that ROS-scavenging capacity determines LAAO accumulation in bacterial cells. Our results shed a light on understanding the mechanism underlying controlling and adapting to LAAO accumulation in. Besides, our findings are critical to the improvement of heterologous expression of active LAAO in the future.

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Advances in Detection Methods of l-Amino Acid Oxidase Activity

Cited by 7 publications

References 66 publications

Exploring Regulation Genes Involved in the Expression of L-Amino Acid Oxidase in Pseudoalteromonas sp. Rf-1

Exploring Regulation Genes Involved in the Expression of L-Amino Acid Oxidase in Pseudoalteromonas sp. Rf-1

Akbu-LAAO exhibits potent anti-tumor activity to HepG2 cells partially through produced H2O2 via TGF-β signal pathway

Reactive oxygen species-scavenging system is involved in l-amino acid oxidase accumulation in Pseudoalteromonas sp. B3

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