Cloning of a thermostable ascorbate oxidase gene from Acremonium sp. HI-25 and modification of the azide sensitivity of the enzyme by site-directed mutagenesis

Takeda, Kayoko; Itoh, Homare; Yoshioka, Ichiro; Yamamoto, Megumi; Misaki, Hideo; Kajita, S.; Shirai, Kengo; Kato, Masashi; Shin, Takashi; Murao, Sawao; Tsukagoshi, Norihiro

doi:10.1016/s0167-4838(98)00206-4

Cited by 13 publications

(8 citation statements)

References 28 publications

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“…MCOs of the basidiomycetes clustered into five major groups. By inclusion of characterized enzymes from other organisms [39,41,55,62,91-93], putative functions for clusters of enzymes were assigned as indicated in Table 1 and Figs. ( 1 and 2 ).…”

Section: Genes For Blue Multi-copper Oxidases In Basidiomycetesmentioning

confidence: 99%

“…In plant ascorbate oxidases, the second M in the motif serves as a fourth copper ligand in T1 [28]. The M is missing in the characterized ascomycete ascorbate oxidase and it is speculated whether the M preceding by two positions can take over the function [39]. However, unlike the Acremonium ascorbate oxidase ASOM ([38,39]; for further discussion see point 5 below), all basidiomycete enzymes in this cluster have the second M (Fig.…”

Section: Definition Of Clusters Of Mcos From Phylogenetic Analysismentioning

confidence: 99%

“…While a broad substrate activity classifies the diphenol oxidising laccases, other MCOs can have a distinct diphenol activity: Oxidation of ascorbate to semidehydroascorbate is performed by ascorbate oxidases [38,39], oxidation of dihydroxyphenylalanine (DOPA) to dopaquinone by pigment MCOs in the DOPA pathway of melanin-synthesis [24]. Other MCOs have ferroxidase activity, i. e. they oxidize Fe 2+ to Fe 3+ [40,41].…”

Section: Introductionmentioning

confidence: 99%

“…2 ) and other studies [30,41,50,54] indicate that in fungi enzymes have undergone separate evolutionary routes towards development of untainted laccase activities (laccases sensu stricto , although such classical or conventional laccases may also have residual ferroxidase activity [41]) and untainted ferroxidase activities (Fet3-type ferroxidases, named after the characterized enzyme Fet3 of the ascomycete Saccharomyces cerevisiae [55] that however has also residual laccase activity [45]), while another evolutionary branch of enzymes contains enzymes of ostensible dual activities (ferroxidases/laccases). Within the fungi, there are also laccase-like enzymes specified on ascorbate oxidation and laccase-like enzymes specified on pigment synthesis [38,39,42,44,53,56]. In conclusion, next to the classical laccases known in multiplicity from white rot and litter decay fungi (basidiomycete laccases sensu stricto ) and also from a number of saprotrophic and plant pathogenic filamentous ascomycetes (ascomycete laccases sensu stricto ), at least three different lines of blue MCOs with residual laccase activity can be distinguished in fungi [30,41,50].…”

Section: Introductionmentioning

confidence: 99%

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Multiple Multi-Copper Oxidase Gene Families in Basidiomycetes – What for?

Kües¹,

Rühl

2011

124

125

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Genome analyses revealed in various basidiomycetes the existence of multiple genes for blue multi-copper oxidases (MCOs). Whole genomes are now available from saprotrophs, white rot and brown rot species, plant and animal pathogens and ectomycorrhizal species. Total numbers (from 1 to 17) and types of mco genes differ between analyzed species with no easy to recognize connection of gene distribution to fungal life styles. Types of mco genes might be present in one and absent in another fungus. Distinct types of genes have been multiplied at speciation in different organisms. Phylogenetic analysis defined different subfamilies of laccases sensu stricto (specific to Agaricomycetes), classical Fe2+-oxidizing Fet3-like ferroxidases, potential ferroxidases/laccases exhibiting either one or both of these enzymatic functions, enzymes clustering with pigment MCOs and putative ascorbate oxidases. Biochemically best described are laccases sensu stricto due to their proposed roles in degradation of wood, straw and plant litter and due to the large interest in these enzymes in biotechnology. However, biological functions of laccases and other MCOs are generally little addressed. Functions in substrate degradation, symbiontic and pathogenic intercations, development, pigmentation and copper homeostasis have been put forward. Evidences for biological functions are in most instances rather circumstantial by correlations of expression. Multiple factors impede research on biological functions such as difficulties of defining suitable biological systems for molecular research, the broad and overlapping substrate spectrum multi-copper oxidases usually possess, the low existent knowledge on their natural substrates, difficulties imposed by low expression or expression of multiple enzymes, and difficulties in expressing enzymes heterologously.

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Section: Genes For Blue Multi-copper Oxidases In Basidiomycetesmentioning

confidence: 99%

Section: Definition Of Clusters Of Mcos From Phylogenetic Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiple Multi-Copper Oxidase Gene Families in Basidiomycetes – What for?

Kües¹,

Rühl

2011

124

125

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“…128 min at 60°C) can be calculated from the data reported for thermostable monomeric AO from Acremonium sp. HI-25 cloned into Aspergillus nidulans (32). Figure 4 shows the semilog plot of k d versus the reciprocal absolute temperature, which allowed estimating the thermodynamic parameters of AO irreversible inactivation ( Table 1).…”

Section: Thermodynamics Of Ao Thermalmentioning

confidence: 99%

Kinetic and Thermodynamic Investigation on Ascorbate Oxidase Activity and Stability of a Cucurbita maxima Extract

Porto

Porto²,

Cavalcanti³

et al. 2006

Biotechnology Progress

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The kinetic and thermodynamic properties of ascorbate oxidase (AO) activity and stability of a Cucurbita maxima extract were investigated. Activity tests performed at 25 degrees C using initial ascorbic acid concentration in the range 50-750 M allowed estimating the Michaelis constant for this substrate (Km = 126 microM) and the maximum initial rate of ascorbic acid oxidation (A0,max = 1.57 mM min-1). The main thermodynamic parameters of the enzyme reaction (DeltaH* = 10.3 kJ mol-1; DeltaG* = 87.2 kJ mol-1; DeltaS* = -258 J mol-1 K-1) were estimated through activity tests performed at 25-48 C. Within such a temperature range, no decrease in the initial reaction rate was detected. The long-term thermostability of the raw extract was then investigated by means of residual activity tests carried out at 10-70 degrees C, which allowed estimating the thermodynamic parameters of the irreversible enzyme inactivation as well (DeltaH*D = 51.7 kJ mol-1; DeltaG*D = 103 kJ mol-1; S*D = -160 J mol-1 K-1). Taking into account the specific rate of AO inactivation determined at different temperatures, we also estimated the enzyme half-life (1047 min at 10 degrees C and 21.2 min at 70 degrees C) and predicted the integral activity of a continuous system using this enzyme preparation. This work should be considered as a preliminary attempt to characterize the AO activity of a C. maxima extract before its concentration by liquid-liquid extraction techniques.

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Purification and Characterization of Multicopper Oxidases for Enzyme Electrodes

Eby

Johnson²

2014

Enzymatic Fuel Cells

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Cloning of a thermostable ascorbate oxidase gene from Acremonium sp. HI-25 and modification of the azide sensitivity of the enzyme by site-directed mutagenesis

Cited by 13 publications

References 28 publications

Multiple Multi-Copper Oxidase Gene Families in Basidiomycetes – What for?

Multiple Multi-Copper Oxidase Gene Families in Basidiomycetes – What for?

Kinetic and Thermodynamic Investigation on Ascorbate Oxidase Activity and Stability of a Cucurbita maxima Extract

Purification and Characterization of Multicopper Oxidases for Enzyme Electrodes

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