Soil maltase activity by a glucose oxidase–perioxidase system

Abstract

The enzyme maltase (glucoinvertase; glucosidosucrase; maltase-glucoamylase; α-glucopyranosidase; glucosidoinvertase; α- d -glucosidase; α-glucoside hydrolase; α-1,4-glucosidase EC 3.2.1.20), is involved in the exo-hydrolysis of 1,4-α-glucosidic linkages and certain oligosaccharides into glucose which is an important energy source for soil microbes. This enzyme originates from different sources, which include plants, seaweeds, protozoa, fungi, bacteria, vertebrates, and invertebrates. The assay of soil maltase using maltose as substrate and the released glucose determined using a glucose oxidase–peroxidase system has not been explored or investigated to the best of our knowledge. A simple assay protocol using this system is proposed to evaluate and characterize maltase activity in soils. The protocol involves the release of glucose (determined using a glucose oxidase–peroxidase colorimetric approach) when 1 g soil is treated with toluene and incubated with 5 mM maltose in 67 mM sodium acetate buffer (pH 5.0) at 37 °C for 1 h. The optimal activity using this procedure was at pH 5.0 and decreased at temperatures above 70 °C. The calculated K m values ranged from 0.8 to 6.5 mM, and are comparable to those of enzymes purified from microorganisms. The Arrhenius equation plots for the activity in the four soils were linear between 20 and 70 °C. The activation energy values ranged from 34.1 to 57.2 kJ mol −1 , the temperature coefficients ( Q 10 ) ranged from 1.5 to 1.9 (avg. = 1.7), and the coefficients of variation (CV) of the proposed assay protocol for the soils used was <6%. While we recognize the availability of established assay protocols to determine soil α-glucosidase (referred in other literature as maltase) activity based on the p -nitrophenol (artificial product) released from p -nitrophenyl-α- d -glucopyranoside (artificial substrate), our interest was to assay its activity by determining the glucose (natural product) released from maltose (natural substrate).

Purification and characterization of a novel α-D-glucosidase from <i>Lactobacillus fermentum</i> with unique substrate specificity towards resistant starch

“…With an increase in the time duration, transglucosidase activity of the purified enzyme was observed. The alphaglucosidase activity was affected in the presence of heavy metals, such as Hg 2+ and Pb 2+ , and this result was in agreement with the available reports (Mfombep and Senwo, 2012). The Hg 2+ ion acts as a strong inhibitor of enzymes isolated from different sources and this suggests the occurrence of thiol groups at the catalytic site of the enzyme (Lasrado and Gudipati, 2013).…”

Biosensor for maltose quantification and estimation of maltase activity

“…In study of Mfomber and Senwo various buffers have been used to assay maltase activity from microbes iso-lated from soil and soil extracts; the authors pointed out that the phosphate buffers have been the most used. [2] In next study Tris buffer inhibited B-4c/3 cells response to maltose as Tris inhibited maltase from the yeast and other sources as reported by Guffanti and Corpe. [29] In contrast to greater Tris inhibition of the pseudomonas enzyme at alkaline than at acid pH, [29] inhibition of the B-4c/3 cells response to maltose by Tris was more pronounced at neutral than at alkaline pH.…”

“…This enzyme originates from different sources, which include plants, seaweeds, protozoa, fungi, bacteria, vertebrates, and invertebrates. [2] The enzymes have been purified and characterized from bacteria, yeasts and moulds, and differ in their substrate specificities. The enzymes from Bacillus strains (B. amylolyticus, B. cereus, B. megaterium, B. subtilis) have been termed "maltases" since they have a high activity towards maltose.…”

Honeydew Deposition by the Giant Willow Aphid (Tuberolachnus salignus) Affects Soil Biota and Soil Biochemical Properties

“…The urease (EC 3.5.1.5), invertase (EC 3.2.1.26), β-amylase (EC 3.2.1.2), α-glucosidase (EC 3.2.1.20), dehydrogenase (EC 1.1.1.1) and amidase (EC 3.5.1.4) activities were assessed according to the protocols developed by Shcherbakova [46], Frankenberger and Johanson [47], Ross [48], Mfombep and Senwo [49], Serra-Wittling, et al [50], Alef and Nannipieri [51] and Frankenberger [52], with slight modifications. Moist soil (1 g dry weight equivalent) was treated with 1.6 mL of triphenyltetrazolium chloride (TTC) before incubating at 30 • C for 24 h; 5 mL of acetone was added followed by incubation in the dark for 2 h to measure the dehydrogenase activity [51].…”