Fluorometric study on the binding of isomaltose and maltose to glucoamylase from Rhizopus niveus.

Ohnishi, Masatake; Wada, Shigehiko; Yamada, Takashi; Tanaka, Akiyoshi; Kitano, Hiromi

doi:10.5458/jag1972.30.57

Cited by 9 publications

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“…23) When isomaltose binds to the enzyme in the productive binding mode to form productive ESp complex, gluconolactone cannot bind to the enzyme-isomaltose complex, since subsite 1 is occupied by the nonreducing end glucose residue of isomaltose. Kp/(Kp+LKq) 0.014, which means that only 1.4% of the q enzyme-isomaltose complex exclude the binding of gluconolactone.…”

Section: Inhibition By Gluconolactone and P-nitrophenyl F3-glucosidementioning

confidence: 99%

Subsite Structure ofRhizopusGlucoamylase for the Hydrolytic Reaction of Isomaltooligosaccharides

Tanaka

Takeda

1994

Bioscience, Biotechnology, and Biochemistry

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Section: Inhibition By Gluconolactone and P-nitrophenyl F3-glucosidementioning

confidence: 99%

Subsite Structure ofRhizopusGlucoamylase for the Hydrolytic Reaction of Isomaltooligosaccharides

Tanaka

Takeda

1994

Bioscience, Biotechnology, and Biochemistry

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Effect of organic solvents on the activity of glucoamylase

Nagamoto

Yasuda

Inoue

1986

Biotech & Bioengineering

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Hydrolyses of maltose, maltotriose, and soluble starch catalyzed by glucoamylase (Asp. Niger) were carried out in the aqueous solutions of methanol, ethanol, ethylene glycol, and 1,4-dioxane at 40 degrees C and at the optimum pH in the respective solutions. By the kinetic analysis based on the subsite model, it was shown that the intrinsic rate constant, K(int), was electrostatically affected by the dielectric constant of the hydroorganic solutions. The affinity of the third subsite, A(3), which affects the apparent rate constant, K(0), was correlated with the xG(tr)'s of maltose and amino acid side chains.

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Synthesis of Methyl 5′‐Thio‐α‐isomaltoside via an Acyclic Monothioacetal and its Behavior toward Glucoamylase

Hashimoto

Kawanishi

Yuasa

1996

Chemistry A European J

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Methyl 5'-thio-α-isomaltoside (1), which contains the ring-sulfur analogue of the nonreducing glucoside of isomaltose, was synthesized from gentiobiose through a novel ring opening-recyclization approach. The nonreducing glucoside of per-O-benzylated phenyl 1-thio-β-gentiobioside underwent O-5'-C-1' bond cleavage with dimethyl-boron bromide and thiolacetic acid to give the acyclic monothioacetal 4 with the 1-thioglucopyranoside at the reducing end intact. The HO-5' group in 4 was inverted by a standard oxidation-reduction process with good efficiency. Recyclization under Mitsunobu condition allowed C-5'-S-1' bond formation with inversion of configuration at C-5', to give 1 after functional group interconversion. TLC analysis showed that 1, unlike isomaltose, was not hydrolyzed by glucoamylase from Rhizopus niveus. A fluorometric assay confirmed that the dissociation constant (K ) for 1 with the enzyme was 39 mM at 20°C, which is comparable with that for isomaltose. A binding assay involving fluorescence titration of the enzyme-1 complex with gluconolactone indicated that the disaccharide 1 was bound to the catalytic and noncatalytic subsites. Since isomaltose is known to bind only to the noncatalytic subsites, this result indicates a relatively high affinity of the 5-thioglucose moiety for the catalytic subsite.

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Fluorometric study on the binding of isomaltose and maltose to glucoamylase from Rhizopus niveus.

Cited by 9 publications

References 1 publication

Subsite Structure ofRhizopusGlucoamylase for the Hydrolytic Reaction of Isomaltooligosaccharides

Subsite Structure ofRhizopusGlucoamylase for the Hydrolytic Reaction of Isomaltooligosaccharides

Effect of organic solvents on the activity of glucoamylase

Synthesis of Methyl 5′‐Thio‐α‐isomaltoside via an Acyclic Monothioacetal and its Behavior toward Glucoamylase

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