Values For Maltose Research Articles

Diastatic power and maltose value: a method for the measurement of amylolytic enzymes in malt

A simple method for measurement of the amylolytic activity of malt has been developed and fully evaluated. The method, termed the Maltose Value (MV) is an extension of previously reported work. Here, the MV method has been studied in detail and all aspects of the assay (sample grinding and extraction, starch hydrolysis, maltose hydrolysis and determination as glucose) have been optimised. The method is highly correlated with other dextrinising power methods. The MV method involves extraction of malt in 0.5% sodium chloride at 30°C for 20 minutes followed by filtration; incubation of an aliquot of the undiluted filtrate with starch solution (pH 4.6) at 30°C for 15 min; termination of reaction with sodium hydroxide solution; dilution of sample in an appropriate buffer; hydrolysis of maltose with a specific α-glucosidase; glucose determination and activity calculation. Unlike all subsequent reducing sugar methods, the maltose value method measures a defined reaction product, maltose, with no requirement to use equations to relate analytical values back to Lintner units. The maltose value method is the first viable method in 130 years that could effectively replace the 1886 Lintner method. © 2021 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling.

FTIR, HATR and FT-Raman studies on the anhydrous and monohydrate species of maltose in aqueous solution

The structures of α- and β-maltose anhydrous and their corresponding monohydrated species were studied combining the FT-IR, FT-Raman and HATR spectra with DFT calculations. The four structures were optimized in gas and aqueous solution by using the hybrid B3LYP/6-31G* method. The self-consistent force field (SCRF) calculations together with the polarized continuum (PCM) model were used to study the systems in solution while the solvation energies were computed using the solvation model (SM). The calculated structural and vibrational properties could explain the anomerization of maltose in solution, as was reported in the literature while the natural bond orbital (NBO) analyses for those species support clearly the mutarotation equilibria between both forms in solution, evidencing the anhydrous forms the equilibrium: α (45%) ⇔ β (55%), similar to that experimentally reported at 20 °C. Bands of all the species observed in the vibrational spectra support the presence of the anomeric species of maltose in solution while the presence of dimeric species justify the intense IR bands observed in the higher wavenumbers region. The similar gap values for maltose and lactose probably justify that these sugars are reducing sugars while the high values in sucrose could explain that it is a non-reducing sugar. On the other hand, the sweeteners cyclamate and saccharine are most reactive in solution than the sugars maltose, lactose and sucrose, as expected due to their ionic characteristics. The predicted vibrational spectra for the four species of maltose show reasonable concordances with the corresponding experimental ones. The f(δC-O-C) force constants of the glycosidic bonds follow the tendency: maltose > lactose > sucrose.

The Relationship between Fructose, Glucose and Maltose Content with Diastase Number and Anti-Pseudomonal Activity of Natural Honey Combined with Potato Starch

Honey whose medicinal uses date from ancient times has been lately rediscovered as therapy for burns. Objective: To evaluate the additive action of potato starch on the antipseudomonal activity of natural honey. Methods: Physicochemical parameters of 6 samples of Algerian honeys were analysed; four parameters were measured, including Diastase, glucose, fructose and maltose. The antibacterial activity was tested using the well-agar diffusion assay. Results: Six honey samples with initial diastase activity between 22.1 and 7.3 Schade units were tested. Glucose, fructose and maltose values range between 21, 45-30, 95%, 25, 20-37, 81% and 4, 72-78, 45% respectively. The zone inhibition diameter (ZID) for the six honey samples without starch against P. aureogenosa ranged between 26 and 31 mm. When starch was mixed with honey and then added to well, a zone inhibition increase diameter (ZIID) 27 and 32 mm. The percentage increase (PI %) was noticed with each variety and it ranged between 3, 57 and 18, 75%. Positive correlation has been established between the zone increase of inhibition and the Diastase number (r value was 0.072 at p<0.05). Conclusion: The use of potato starch allows honey benefit and would constitute an additive effect to the antibacterial activity of natural honey.

Studies on the Functional and Processing Properties of Novelty Polished, Waxy and High-amylose Wheat Flours

Functional and processing properties of novel wheat flours, such as polished, waxy and high-amylose wheat flours were determined. Polished flours increased the amounts of minerals and anti-oxidant activity, and the amounts of dietary fibers, phytic acids, ferulic acids and pentosans were 2, 3, 10 and 2 times more, and large amounts of damaged starches and higher maltose values were obtained, as compared with the common flour of CW. The distributions of proteins in polished flours were different depending on the portions (fractions) of wheat grains, and proteins of the innermost fraction showed low-allergic reactions. Baking method including long fermentation significantly improved the baking properties of polished flours, and especially sourdough method increased the free amino acids, reducing sugars and organic acids during fermentation. The CO2 gas in polished-flour-sourdoughs distinctly increased, and their pH, total titratable acidity levels and buffering capacity were significantly better than the CW-sourdough. As a result, the growth of lactic acid bacteria and yeasts in polished-flour-sourdoughs were accelerated during fermentation, and its substituted breads with middle or innermost fractions improved baking qualities having favorable volatile compounds, such as iso-butanol and β-phenyl ethyl alcohol, more than CW-sourdough bread. In contrast, waxy wheat flours improved the staleness of breadcrumbs during storage and its freshness after reheating, while high-amylose wheat flours increased amounts of resistant starch in breadcrumbs during storage. Moreover, waxy wheat flours increased viscous and sticky textures of boiled-noodles, and high-amylose wheat flours suppressed the damage of noodles during boiling with the similar qualities to the durum pasta. Consequently, these novel wheat flours would be sufficient foodstuffs with excellently nutritious, functional and processing properties to give additional values of new taste or functionality to their final products.

Amino Acids that Confer Transport of Raffinose and Maltose Sugars in the Raffinose Permease (RafB) of Escherichia coli as Implicated by Spontaneous Mutations at Val-35, Ser-138, Ser-139, Gly-389 and Ile-391

In order to identify amino acid residues in the Escherichia coli raffinose-H(+) permease (RafB) that play a role in sugar selection and transport, we first incubated E. coli HS4006 containing plasmid pRU600 (expresses inducible raffinose permease and alpha-galactosidase) on maltose MacConkey indicator plates overnight. Initially, all colonies were white, indicating no fermentation of maltose. Upon further incubation, 100 mutants appeared red. pRU600 DNA was prepared from 55 mutants. Five mutants transferred the phenotype for fermentation of maltose (red). Plasmid DNA from five maltose-positive phenotype transformants was prepared and sequenced, revealing three distinct types of mutations. Two mutants exhibited Val-35-->Ala (MT1); one mutant had Ile-391-->Ser (MT2); and two mutants had Ser-138-->Asp, Ser-139-->Leu and Gly-389-->Ala (MT3). Transport studies of [(3)H]-maltose showed that cells harboring MT1, MT2 and MT3 had greater uptake (P <or= 0.05) than cells harboring wild-type RafB. However, [(14)C]-raffinose uptake was reduced in all mutant cells (P <or= 0.05) with MT1, MT2 and MT3 mutants compared to cells harboring wild-type RafB. Kinetic analysis showed enhanced apparent K (m) values for maltose and reduced V (max)/ K (m) ratios for raffinose compared to wild-type values. The apparent K (i) value of maltose for RafB indicates a competitive relationship between maltose and raffinose. Maltose "uphill" accumulation was greater for mutants (P <or= 0.05) than for cells with wild-type RafB. Thus, we implicate residues in RafB that are responsible for raffinose transport and suggest that the substituted residues in RafB dictate structures that enhance transport of maltose.

A fluorescence resonance energy transfer sensor based on maltose binding protein.

A fluorescence resonance energy-transfer (FRET) sensing system for maltose based on E. coli maltose binding protein (MBP) is demonstrated. The FRET donor portion of the sensing system consists of MBP modified with long wavelength-excitable cyanine dyes (Cy3 or Cy3.5). The novel acceptor portion of the sensor consists of beta-cyclodextrin (beta-CD) modified with either the cyanine dye Cy5 or the dark quencher QSY9. Binding of the modified beta-CD to dye-conjugated MBP results in assembly of the FRET complex. Added maltose displaces the beta-CD-dye adduct and disrupts the FRET complex, resulting in a direct change in fluorescence of the donor moiety. In the use of these FRET pairs, MBP dissociation values for maltose were estimated (0.14-2.90 microM). Maltose limits of detection were in the 50-100 nm range.

Change in maltose- and soluble starch-hydrolyzing activities of chimeric α-glucosidases of Mucor javanicus and Aspergillus oryzae

The chimeric α-glucosidases of Mucor javanicus and Aspergillus oryzae, which has high activity toward not only maltooligosaccharides but also soluble starch and has high activity toward maltooligosaccharides but faint activity toward soluble starch, respectively, were constructed by shuffling the C-terminal regions where low homology is observed between the two enzymes. The chimera genes were expressed in Pichia pastoris to produce and secrete the enzymes that have predicted molecular masses in the culture medium. The two chimeric M. javanicus α-glucosidases, of which the N- and C-terminal regions are substituted for those of A. oryzae, respectively, decreased in soluble starch-hydrolyzing activity, however, increased in maltose-hydrolyzing activity by 2.1 and 4.9 times higher than that of the native form of M. javanicus α-glucosidase, respectively. The chimeric enzymes changed on the V max values for maltose significantly, whereas the K m values were similar to that of the native enzyme.

Purification and substrate specificity of honeybee, Apis mellifera L., alpha-glucosidase III.

Alpha-glucosidase III, which was different in substrate specificity from honeybee alpha-glucosidases I and II, was purified as an electrophoretically homogeneous protein from honeybees, by salting-out chromatography, DEAE-cellulose, DEAE-Sepharose CL-6B, Bio-Gel P-150, and CM-Toyopearl 650M column chromatographies. The enzyme preparation was confirmed to be a monomeric protein and a glycoprotein containing about 7.4% of carbohydrate. The molecular weight was estimated to approximately 68,000, and the optimum pH was 5.5. The substrate specificity of alpha-glucosidase III was kinetically investigated. The enzyme did not show unusual kinetics, such as the allosteric behaviors observed in alpha-glucosidases I and II, which are monomeric proteins. The enzyme was characterized by the ability to rapidly hydrolyze sucrose, phenyl alpha-glucoside, maltose, and maltotriose, and by extremely high Km for substrates, compared with those of alpha-glucosidases I and II. Especially, maltotriose was hydrolyzed over 3 times as rapidly as maltose. However, maltooligosaccharides of four or more in the degree of polymerization were slowly degraded. The relative rates of the k0 values for maltose, sucrose, p-nitrophenyl alpha-glucoside and maltotriose were estimated to be 100, 527, 281 and 364, and the Km values for these substrates, 11, 30, 13, and 10 mM, respectively. The subsite affinities (Ai's) in the active site were tentatively evaluated from the rate parameters for maltooligosaccharides. In this enzyme, it was peculiar that the Ai value at subsite 3 was larger than that of subsite 1.

Determination of oligosaccharides in Brazilian honeys of different botanical origin

The levels of 10 oligosaccharides in 70 genuine Brazilian honeys of different floral types are reported. The contents of sucrose and isomaltose were broad, ranging from mean values of 0.07–0.77 and 0.18–0.71%, respectively. The mean values for maltose were in the range 1.58 to 3.77%. The level of turanose (0.78–2.03%) was similar to that of nigerose (1.11–2.81%). Low amounts of melibiose (0.05–0.15%) and panose (0.03–0.08%) were found in Brazilian honeys. Maltotriose, melezitose and raffinose, were present with mean values of 0.24–1.03, 0.21–0.37 and 0.10–0.25%, respectively. Between Brazilian states, honeys from São Paulo had mean values for melibiose significantly ( P<0.05) lower than those from the Minas Gerais and Rio de Janeiro. The mean values for maltose and nigerose found in the Mato Grosso do Sul and Goiás states were significantly higher than from the Mato Grosso state. Honey samples from the Paraná state showed a mean value for maltotriose significantly higher than that from the Rio Grande do Sul state. The contents of maltose, nigerose, turanose and maltotriose proved to be useful for the differentiation of honey samples from different geographical regions and also may be valuable for testing the authenticity of Brazilian honeys.

Digestibility of the hydrogenated derivative of an isomaltooligosaccharide mixture by rats.

The digestibility of the hydrogenated derivative of an isomaltooligosaccharide mixture (IMO-H) was investigated. In an in vitro experiment, the digestibility of IMO-H was examined by models of the digestive system. IMO-H was resistant to two types of alpha-amylase and to artificial gastric juice. Enzymes in the rat small intestinal mucosa hydrolyzed tri-, tetra- and higher saccharide alcohols to disaccharide alcohol, removing successive glucose units from the non-reducing ends of the chains. The hydrolysis ratio for IMO-H was intermediate between the values for maltose and maltitol. In an in vivo study, growing rats were fed on an experimental diet containing IMO-H, maltitol, or hydrogenated palatinose in the range from 5% to 20%. The growth parameters of the rats fed on the test sugar show that the availability of IMO-H was about 1.2 to 1.25 times that of maltitol or hydrogenated palatinose.

Site-directed mutagenesis of the catalytic base glutamic acid 400 in glucoamylase from Aspergillus niger and of tyrosine 48 and glutamine 401, both hydrogen-bonded to the gamma-carboxylate group of glutamic acid 400.

Replacement of the catalytic base Glu400 by glutamine in glucoamylase from Aspergillus niger affects both substrates ground-state binding and transition-state stabilization. Compared to those of the wild-type enzyme, Km values for maltose and maltoheptaose are 12- and 3-fold higher for the Glu400-->Gln mutant, with kcat values 35- and 60-fold lower, respectively, for the same substrates. This unusually high residual activity for a glycosylase mutant at a putative catalytic group is tentatively explained by a reorganization of the hydrogen bond network, using the crystal structure of the related Aspergillus awamori var. X100 glucoamylase in complex with 1-deoxynojirimycin [Harris, E. M. S., Aleshin, A. E., Firsov, L. M., & Honzatko, R. B. (1993) Biochemistry 32, 1618-1626]. Supposedly Gln400 in the mutant hydrogen bonds to the invariant Tyr48, as does Glu400 in the wild-type enzyme. For Tyr48-->Trp A. niger glucoamylase kcat is reduced 80-100-fold, while Km is increased only 2-3-fold. Gln401 also hydrogen bonds to Glu400, but its mutation to glutamic acid has only a minor effect on activity. The Tyr48-->Trp and Glu400-->Gln glucoamylases share particular features in displaying unusually high activity below pH 4.0-which reflects lack of the wild-type catalytic base function- and unusually low binding affinity at subsite 2. Both mutants have lost 13-16 kJ mol-1 in transition-state stabilization energy.(ABSTRACT TRUNCATED AT 250 WORDS)

Purification and properties of two forms of glucoamylase from Saccharomycopsis fibuligera

Two forms of glucoamylase were formed in the filtrate of a 6-d culture of Saccharomycopsis fibuligera that had been cultivated under aerobic conditions with an oxygen-transfer rate of 35 × 10 −7 g mol/ml/min. The glucoamylases, designated as I and II, resembled each other in termes of pH stability, optimum temperature and the effects of various chemicals on enzymatic activity, but the molecular weights (55,000 and 56,000, respectively), isoelectric points (6.5 and 6.1, respectively), thermal stability, and K m values for maltose differed between the two enzymes.

Characterization of symbiosis specific forms of alpha-glucosidase from Glycine max root nodules

Summary Three forms of α-glucosidase (EC 3.2.1.20) were isolated from soybean ( Glycine max L. Merr. cv. Maple Arrow) root nodules and two of them were further purified by a procedure including fractionation with PEG-8,000 followed by Q-Sepharose, S-Sepharose, Chromatofocusing and Superose 6 column chromatography. Chromatofocusing of the plant soluble fraction yielded two different isoforms, which were designated as I and II. Their isoelectric points were 7.3 (I) and 6.5 (II) as determined by native isoelectric focusing. The α-glucosidase I was further purified 502-fold to a specific activity of 1.8 units (mgprotein) -1 . In the peribacteroid space only one form, designated III, was resolved by chromatofocusing. The isoelectric point was 7.2 estimated by native isoelectric focusing. The α-glucosidase III was purified 86-fold to a specific activity of 3.1 units (mg protein) -1 . The α-glucosidases I and II had similar properties. The pH-optima were 5.2 (I) and 4.8 (III). The subunit molecular weights for α-glucosidase I and α-glucosidase III were estimated by SDS-PAGE to be 65 kDa and 66 kDa, respectively. Both enzymes hydrolyzed maltose, maltotriose, isomaltose and dextrin. Starch was only weakly hydrolyzed and neither a-glucosidase acted on sucrose. K m values for maltose were 0.91 mM (I) and 0.67 mM (III), and for PNPG 0.37 mM (I) and 0.76 mM (III). Ag + and Fe 2+ were the most potent inhibitors of both enzymes. The functions of these enzymes in the symbiotic compartments are discussed.

Characterization of thermostable ?-glucosidase from Clostridium thermohydrosulfuricum 39E

Clostridium thermohydrosulfuricum 39E produced a cell-bound α-glucosidase. It was partially purified 140-fold by solubilizing with Triton X-100, ammonium sulfate treatment, DEAE-Sepharose CL-6B, octyl-Sepharose and acarbose-Sepharose affinity chromatography. The optimum temperature for the action of the enzyme was at 75°C. It had a half-life of 35 min at 75°C, 110 min at 70°C and 46 h at 60°C. The enzyme was stable at pH 5.0–6.0 and had an optimum pH at 5.0–5.5. It hydrolyzed the α-1,4-linkages in maltose, maltotriose, maltotetraose and maltohexaose, the rate decreasing in order of higher-sized oligosaccharides. The enzyme preparation also hydrolyzed the α-1,6 linkages in isomaltose and isomaltotriose. It rapidly hydrolyzed p-nitrophenyl α-d-glucoside (pNPG). The Km values for maltose, isomaltose, panose, maltotriose, and pNPG were 1.85, 2.95, 1.72, 0.58, and 0.31 mm, respectively, at pH 5.5 and 60°C. The enzyme produced glucose from all these substrates. The enzyme preparation did not require any metal ion for activity. The α-glucosidase activity was inhibited by acarbose.

Purification and properties of α-glucosidase from suspension-cultured sugar-beet cells

The main α-glucosidase from sugar-beet cells has been isolated by a procedure including fractionation with ammonium sulphate, Sephacryl S-200 HR column chromatography, CM-cellulose column chromatography, Mono Q column chromatography, and preparative disc gel electrophoresis. The M r of the enzyme was 53 000. The enzyme hydrolysed maltooligosaccharides at a faster rate than maltose. The K m values for maltose and maltohexaose were 3.5 and 0.35 mM.

Partial Characterization and Subcellular Localization of Three α-Glucosidase Isoforms in Pea (Pisum sativum L.) Seedlings

Three isoforms of alpha-glucosidase (EC 3.2.1.20) have been extracted from pea (Pisum sativum L.) seedlings and separated by DEAE-cellulose and CM-Sepharose chromatography. Two alpha-glucosidase isoforms (alphaG1 and alphaG2) were most active under acid conditions, and appeared to be apoplastic. A neutral form (alphaG3) was most active near pH 7, and was identified as a chloroplastic enzyme. Together, the activity of alphaG1 and alphaG2 in apoplastic preparations accounted for 21% of the total acid alpha-glucosidase activity recovered from pea stems. The vast majority (86%) of the apoplastic acid alpha-glucosidase activity was due to alphaG1. The apparent K(m) values for maltose of alphaG1 and alphaG2 were 0.3 and 1.3 millimolar, respectively. The apparent K(m) for maltose of alphaG3 was 33 millimolar. The respective native molecular weights of alphaG1, alphaG2, and alphaG3 were 125,000, 150,000, and 110,000.

Allosteric Properties, Substrate Specificity, and Subsite Affinities of Honeybee α-Glucosidase I

The substrate specificity of honeybee alpha-glucosidase I, a monomeric enzyme was kinetically investigated. Unusual kinetic features were observed in the cleavage reactions of sucrose, maltose, p-nitrophenyl alpha-glucoside, phenyl alpha-glucoside, turanose, and maltodextrin (DP = 13). At relatively high substrate concentrations, the velocities of liberation of fructose from sucrose, glucose from maltose, p-nitrophenol from p-nitrophenyl alpha-glucoside, and phenol from phenyl alpha-glucoside were accelerated, and so the Lineweaver-Burk plots were convex, indicating negative kinetic cooperativity: the Hill coefficients were calculated to be 0.50, 0.64, 0.50, and 0.67 for sucrose, maltose, p-nitrophenyl alpha-glucoside, and phenyl alpha-glucoside, respectively. For the degradation of turanose and maltodextrin, the enzyme showed a sigmoidal curve in v versus s plots and thus catalyzed the reaction with positive kinetic cooperativity. The Lineweaver-Burk plots were concave and the Hill coefficients were 1.2 and 1.5 for turanose and maltodextrin, respectively. These unique properties cannot be interpreted by the reaction mechanism that Huber and Thompson proposed: (1973) Biochemistry 12, 4011-4020. The rate parameters for the hydrolysis of sucrose, maltose, p-nitrophenyl alpha-glucoside and phenyl alpha-glucoside were estimated by extrapolating the linear part of the Lineweaver-Burk plots at low substrate concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Single active site mechanism of rabbit liver acid alpha-glucosidase.

An acid alpha-glucosidase was purified from rabbit liver by fractionation with ammonium sulfate, and chromatographies on Sephadex G-100, CM-Toyopearl, Toyopearl HW-55F, and Toyopearl HW-65F column. The resulting preparation showed a single band on polyacrylamide disc gel electrophoresis. The molecular weight was estimated to be 1.03 X 10(4) by SDS-disc electrophoresis. The optimum pH was found to be 4.7. The alpha-glucosidase showed relatively high activity not only toward maltose but also toward alpha-glucans, such as shellfish glycogen, soluble starch, beta-limit dextrin, amylopectin, and amylose. The Km values for maltose and shellfish glycogen were 2.1 and 16 mM (the concentration of non-reducing glucose units), respectively, and the ratio of maximum velocities of hydrolysis of the two substrates was 100:133. The nature of the active site catalyzing the hydrolyses of maltose and shellfish glycogen was investigated by electrophoresis in the presence of urea and by kinetic methods. The purified enzyme was not separated into two components, maltase and glycogen hydrolase, in the electrophoretic gel containing 3 M urea, contrary to the report by Belenki and Rosenfeld ((1972) Biochem. Biophys. Res. Commun. 46, 443-448). In experiments with mixed substrates of maltose and glycogen, the kinetic features agreed very closely with those theoretically predicted for a single site mechanism. The essential ionizable groups, 1 (on the acidic side) and 2 (on the alkaline side), were identified as -COO- and -COOH for the hydrolysis of both substrates. Cations, Na+, K+, Mg2+, were about equally effective for the stimulation of enzyme action on maltose and glycogen.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition by maltose, isomaltose, and nigerose of the synthesis of high-molecular-weight d-glucans by the d- glucosyltransferases of Streptococcus sobrinus

Two d-glucosyltransferases are produced by Streptococcus sobrinus C211. One (GTF-S) catalyzes the conversion of sucrose into soluble α-(1→6)-linked α- (1→3)-branched d-glucans, and the other (GTF-I), of sucrose into α-(1→3)-linked α-(1→6)-branched d-glucans. These enzymes were studied by using maltose, isomaltose, and nigerose as inhibitors. Maltose and isomaltose were found to be competitive inhibitors of GTF-S, whereas nigerose has no effect on GTF-S activity. The K i values for maltose and isomaltose were determined to be 11 and 15m m, respectively. Maltose, isomaltose, and nigerose competitively inhibit GTF-I. The K i values for these inhibitors were found to be ∼0.8, 2.5, and 15m m, respectively. The inhibitory properties of each disaccharide are interpreted in terms of conformational comparisons with sucrose.

Purification and some properties of two .ALPHA.-glucosidases in glutinous rice seed.

Two α-glucosidases were highly purified from glutinous rice seed by fractionation with am monium sulfate, CM-Sepharose CL-6B ion-exchange column chromatography, gel filtration, and preparative disc electrophoresis. The molecular weights were estimated to be 9.3×104 for α-glucosidase I and 8.6×104 for α-glucosidase II by SDS disc electrophoresis. The pH optima were 4.5 for α-glucosidase I and 4.3 for α-glucosidase II, and the pH stabilities of both enzymes were in the range of pH 3.5-10. α-Glucosidase I and α-glucosidase II were stable up to 40 and 50°C, respectively. The both α-glucosidases attacked not only maltose but also soluble starch. The Km values for maltose were 4.8 mM for α-glucosidase I and 2.0 mM for α-glucosidase II, and those for soluble starch were 1.7 mM for α-glucosidase I and 1.1 mM for α-glucosidase II, in the concentration of non-reducing terminal glucose. The ratios of the V values of hydrolyses of maltose to those of soluble starch were 100 : 118 for α-glucosidase I and 100 : 148 for α-glucosidase II.