Enzymic Properties of Three β-Glucosidases from<i>Aspergillus aculeatus</i>No. F-50

Sakamoto, Reiichiro; Arai, Motoo; Murao, Sawao

doi:10.1080/00021369.1985.10866915

Cited by 7 publications

(4 citation statements)

References 3 publications

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“… Two glucose molecules are located in the active-site cavity at subsites −1 and +1 (following the suggested numbering sequence where the scissile bond is between these subsites). A long cleft begins at subsite +1 and extends past subsite +4 (seen bound to the cryoprotectant molecule 2-methyl-2,4-pentanediol), which explains the high activity of this β-glucosidase toward longer oligosaccharides . However, this promiscuous nature of the active site can also lead to nonproductive substrate binding to subsites +1/+2, as is frequently observed for oligomer-active enzymes in the presence of disaccharide substrates .…”

Section: Resultsmentioning

confidence: 95%

“…A long cleft begins at subsite +1 and extends past subsite +4 (seen bound to the cryoprotectant molecule 2-methyl-2,4pentanediol), which explains the high activity of this βglucosidase toward longer oligosaccharides. 92 However, this promiscuous nature of the active site can also lead to nonproductive substrate binding to subsites +1/+2, 7 as is frequently observed for oligomer-active enzymes in the presence of disaccharide substrates. 93 Although the binding affinities and locations of glucose moieties can vary greatly for different β-glucosidases, in general, activation can be achieved through selective substrate-accessibility changes.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Enhanced Activity of the Cellulase Enzyme β-Glucosidase upon Addition of an Azobenzene-Based Surfactant

Seidel

Lee

2020

ACS Sustainable Chem. Eng.

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β-Glucosidases catalyze the hydrolysis of cellobiose to glucose, which is often the rate-limiting step in the conversion of cellulose into fermentable sugars during bioethanol production. Thus, the structure and function of β-glucosidase from Aspergillus niger were examined in response to a photoresponsive azobenzene-based surfactant (4ethyl-4′(trimethylamino-butoxy)azobenzene bromide, azoTAB) as a means to enhance the enzyme activity. Light and neutron scattering data indicate that pure β-glucosidase exists as dimers or higher aggregates in solution that are progressively converted to monomers with an increasing azoTAB concentration. This transition is accompanied by a 60% increase in catalytic activity. In contrast, the enzyme is simply deactivated in the presence of conventional straight-chain hydrocarbon surfactants. Shape-reconstructed images obtained from SANS data demonstrate that azoTAB causes selective unfolding in the α/β sandwich domain that comprises the crystallographic dimer interface, consistent with the observed transition to monomers. Furthermore, this domain forms one side of a long cleft that begins at the active site and facilitates the nonproductive binding of substrate or longer oligosaccharides, which at times can block the active site. Indeed, kinetic data indicate that the azoTAB-induced increase in β-glucosidase activity is a result of diminished substrate inhibition, thus providing a unique means of obtaining glucose-tolerant β-glucosidases.

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Section: Resultsmentioning

confidence: 95%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Enhanced Activity of the Cellulase Enzyme β-Glucosidase upon Addition of an Azobenzene-Based Surfactant

Seidel

Lee

2020

ACS Sustainable Chem. Eng.

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“…In addition, no effect of albumin on the activity of G 1 or G2 was observed, differing from the fJ-glucosidases of A. aculeatus. 23 Enzyme (Gl or G2) ofO.014unit was used. (A), Effects of pH on activity.…”

Section: Effects Of Various Reagents On Activitymentioning

confidence: 99%

Purification and Properties of Twoβ-Glucosidases fromPenicillium herqueiBanier and Sartory

Funaguma

Hara

1988

Agricultural and Biological Chemistry

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Two p-glucosidases, Gland G2, were purified from the culture supernatant of Penicillium herquei Banier and Sartory. Both the purified enzymes were homogeneous on polyacrylamide disc gel electrophoresis. The molecular weights of G I and G2 were estimated to be 125,000 and 122,000, respectively, by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. G I and G2 contained 12.7% and 16.1 % carbohydrate as glucose, and had isoelectric points of 5.02 and 5.24, respectively. Both enzymes had optimum pHs of 4.0 ~4.5 and optimum temperatures at 60°C, but pH-and thermo-stabilities of G 1 were' higher than those of G2. Both enzymes were active not only on p-nitrophenyl P-D-glucopyranoside, salicin, and the p-glucobioses tested but also on laminarin. CM-Cellulose was a very poor substrate for both enzymes. The activities of G 1 toward the substrates except for laminarin and CM-cellulose were apparently higher than those of G2. Both enzymes acted on cellobiose to produce a transfer product.

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“…One is hydrolases such as those of Aspergillus aculeatus 23 ) and Talaromyces emersonU 24 ) and another is transglucosidases such as those of Alcaligenes jaecalis 20 ) and Aspergillus niger. 2S) The glucosidase III from Streptomyces sp.…”

Section: Action Of the F3-g1ucosidase Ilion Gluco-mentioning

confidence: 99%