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At least 307 records · Page 17Linked to original sources
PubMed1986

Interaction of hepatic asialoglycoprotein receptor with asialoorosomucoid and galactolyzed lysosomal alpha-glucosidase.

An asialoglycoprotein receptor was isolated from murine liver and purified more than 1600-fold using 2-fold affinity chromatography on asialoorosomucoid-Sepharose. The purified receptor did not interact with 125I-orosomucoid, but bound to 125I-asialoorosomucoid. The binding of the receptor to asialoorosomucoid was saturable. The dissociation constant of the receptor-asialoorosomucoid complex was 0.4 X 10(-9) M. The molecular mass of the receptor, as determined with the use of specific antibodies by the immunoblotting method, was 43 kDa. High concentrations of unlabeled asialoorosomucoid and of n-aminophenyl-beta-D-galactosyl derivatives of bovine serum albumin, ovalbumin and acid alpha-glucosidase from human liver inhibited the binding of the receptor to 125I-asialoorosomucoid almost completely. The binding of the receptor to 125I-galactolyzed alpha-glucosidase was pH-dependent, with the pH optimum at 8.0-9.0. It was shown that, as in the case of 125I-asialoorosomucoid, the binding of the 125I-galactosyl derivative of alpha-glucosidase occurred in the presence of Ca2+ and was inhibited by N-acetylgalactosamine. Glycoproteins containing galactose as a terminal residue inhibited the interaction of the receptor with 125I-galactolyzed alpha-glucosidase. The possibility of directed transport of the galactolyzed alpha-glucosidase derivative into parenchymous liver cells using receptor-mediated endocytosis is discussed.

Acetylgalactosamine↗
PubMed1990

Beta-glucosidase activity in liver, spleen and brain in acute neuropathic Gaucher disease.

We examined the property of beta-D-glucosidase in normal child liver, spleen and brain tissues and in tissues affected by Gaucher disease using two different kinds of synthetic substrates, 2-hexadecanoylamino-4-nitrophenyl-beta-D-glucopyranoside (HN Glc) and 4-methylumbelliferyl-beta-D-glucopyranoside (MU Glc). HN glucosidase activity was noted only in the particulate fraction of each organ tissues of the normal child, and it was deficient in the tissue affected by Gaucher disease. MU glucosidase activity in the whole homogenate and the soluble fraction showed normal levels for the liver and brain tissue of the Gaucher patient. However, MU glucosidase activity in the particulate fraction, at the vicinity of pH 4.5, for the liver, spleen and brain tissue was deficient in the affected patient. HN Glc was a very easy and useful substrate for the diagnosis of Gaucher disease, but it was not very sensitive. While MU Glc was very sensitive, it was necessary to remove the non-specific beta-D-glucosidase for the diagnosis of Gaucher disease.

Brain↗
PubMed1998

Complete correction of acid alpha-glucosidase deficiency in Pompe disease fibroblasts in vitro, and lysosomally targeted expression in neonatal rat cardiac and skeletal muscle.

The enzyme acid alpha-glucosidase catalyzes the breakdown of lysosomal glycogen. Absence of this enzyme results in infantile Pompe disease, characterized by hypertrophic cardiomyopathy, skeletal muscle weakness and fatal heart failure by 2 years of age. We have examined the possibility of gene replacement therapy for this disease, by constructing an E1-deleted recombinant adenovirus encoding human acid alpha-glucosidase (Ad-GAA). The dose-response in fibroblasts from patients with Pompe disease transduced with this vector is linear over the range tested (one to 2000 plaque forming units (p.f.u.) of Ad-GAA per cell), and acid alpha-glucosidase activity comparable to that of normal fibroblasts is achieved at 100 p.f.u. per cell. Targeting of the recombinant protein to the lysosomal compartment was confirmed by immunocytochemistry. In vivo expression was examined by injecting Ad-GAA into newborn rats; intracardiac administration produced 10 times the normal level of acid alpha-glucosidase activity in whole heart lysates, while a hind-limb i.m. injection increased activity in that muscle to six times the normal level. Western blotting of these tissues defected species at 76 kDa consistent with the size of processed lysosomal enzyme, and levels of expression as high as 1.0 mg recombinant protein per gram of tissue wet weight were produced. These data demonstrate high-level, lysosomal expression of recombinant acid alpha-glucosidase in treated target tissues and support the feasibility of gene replacement strategies for Pompe disease.

Adenoviridae↗
PubMed1998

Substrate binding and catalytic mechanism of a barley beta-D-Glucosidase/(1,4)-beta-D-glucan exohydrolase.

A beta-glucosidase, designated isoenzyme betaII, from germinated barley (Hordeum vulgare L.) hydrolyzes aryl-beta-glucosides and shares a high level of amino acid sequence similarity with beta-glucosidases of diverse origin. It releases glucose from the non-reducing termini of cellodextrins with catalytic efficiency factors, kcat/Km, that increase approximately 9-fold as the degree of polymerization of these substrates increases from 2 to 6. Thus, the enzyme has a specificity and action pattern characteristic of both beta-glucosidases (EC 3.2.1.21) and the polysaccharide exohydrolase, (1,4)-beta-glucan glucohydrolase (EC 3.2.1.74). At high concentrations (100 mM) of 4-nitrophenyl beta-glucoside, beta-glucosidase isoenzyme betaII catalyzes glycosyl transfer reactions, which generate 4-nitrophenyl-beta-laminaribioside, -cellobioside, and -gentiobioside. Subsite mapping with cellooligosaccharides indicates that the barley beta-glucosidase isoenzyme betaII has six substrate-binding subsites, each of which binds an individual beta-glucosyl residue. Amino acid residues Glu181 and Glu391 are identified as the probable catalytic acid and catalytic nucleophile, respectively. The enzyme is a family 1 glycoside hydrolase that is likely to adopt a (beta/alpha)8 barrel fold and in which the catalytic amino acid residues appear to be located at the bottom of a funnel-shaped pocket in the enzyme.

Amino Acid Sequence↗
PubMed1986

Immunolocalization of the oligosaccharide trimming enzyme glucosidase II.

We used immunoelectron microscopy to localize glucosidase II in pig hepatocytes. The enzyme trims the two inner alpha 1,3-linked glucoses from N-linked oligosaccharide precursor chains of glycoproteins. Immunoreactive enzyme was concentrated in rough (RER) and smooth (SER) endoplasmic reticulum but not detectable in Golgi apparatus cisternae. Transitional elements of RER and smooth membraned structures close to Golgi apparatus cisternae contained labeling for glucosidase II. Specific labeling was also found in autophagosomes. These results indicate strongly that glucosidase II acts on glycoproteins before their transport to, and processing in Golgi apparatus cisternae, and suggest that an important transitional region for glucosidase II exists between RER and Golgi apparatus cisternae. Degradation in autophagolysosomes could form a normal catabolic pathway for glucosidase II.

Animals↗
PubMed1994

The effect of a single base pair deletion (delta T525) and a C1634T missense mutation (pro545leu) on the expression of lysosomal alpha-glucosidase in patients with glycogen storage disease type II.

Glycogen storage disease type II (GSDII, Pompe's disease) is caused by an autosomal recessive inheritance of lysosomal alpha-glucosidase deficiency. By sequence analysis we have identified the mutations in the lysosomal alpha-glucosidase gene (GAA) of two unrelated patients, who have one and two copies, respectively, of the same missense mutation. The milder affected adult patient was found to be homozygous for a C1634T transition resulting in the substitution of pro545 by leu. The more severely affected adolescent patient had this same mutant allele combined with a 1 base pair deletion (delta T525) in the second allele causing premature termination at nucleotide positions 658-660. Both these mutations were introduced in wild-type alpha-glucosidase cDNA and expressed in COS-1 cells to analyse their effect. The delta T525 mutation prohibits the formation of lysosomal alpha-glucosidase completely. The pro545-->leu substitution is compatible with normal synthesis but hampers enzyme maturation and results in a 92% net loss of lysosomal alpha-glucosidase activity. The patient with adult GSDII has, in accordance with the allelic constitution, a 2-fold higher residual activity than the patient with juvenile GSDII. The delta T525 deletion was detected in two other unrelated patients, and also the C1634T transition was encountered in two more Caucasian patients with GSDII.

Adolescent↗
PubMed1984

Kinetic studies on the substrate specificity and active site of rabbit muscle acid alpha-glucosidase.

Mammalian muscle acid alpha-glucosidase was highly purified for the first time from rabbit muscle by fractionation with ammonium sulfate, and chromatographies on Sephadex G-100, CM-TOYOPEARL and TOYOPEARL HW-55. The resulting preparation showed a single band on polyacrylamide disc gel electrophoresis. The molecular weight was estimated to be 1.02 X 10(5) by SDS-electrophoresis. The optimum pH was found to be 4.5. The alpha-glucosidase showed relatively high activity not only toward maltose but also toward alpha-glucans, such as soluble starch, beta-limit dextrin, amylopectin, shellfish glycogen, and amylose. The Km values for maltose and glycogen were 6.3 mM and 12 mM (the concentration of non-reducing glucose units), respectively, and the ratio of the maximum velocities of hydrolyses of the two substrates was 100:66.7, in that order. Rabbit muscle acid alpha-glucosidase showed a wide specificity for various substrates. The Km values for maltose, maltotriose, -tetraose, -pentaose, -hexaose, -heptaose, and -octaose, and maltodextrins of average polymerization degrees of 13 and 17 were 6.3 mM, 2.6 mM, 5.9 mM, 3.0 mM, 5.9 mM, 5.9 mM, 5.9 mM, 7.7 mM, and 5.6 mM, respectively. The relative maximum velocities for maltooligosaccharides consisting of three or more glucose units were 43.5-89.3% of that for maltose. For disaccharides, the rate of hydrolysis decreased in the following order: maltose divided by nigerose greater than kojibiose greater than isomaltose. The purified enzyme was a typical acid alpha-glucosidase of mammalian origin, which hydrolyzed various substrates to produce alpha-glucose. The nature of the active site catalyzing the hydrolyses of maltose and glycogen was investigated by some kinetic methods. In experiments with mixed substrates, maltose and shellfish 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+, and Mg2+, were about equally effective for stimulation of the enzyme actions on maltose and shellfish glycogen. Tris, turanose and erythritol inhibited not only maltase activity but also glucoamylase activity of the enzyme. From these results, it was concluded that rabbit muscle acid alpha-glucosidase attacks maltose and glycogen by a single active site mechanism.

Animals↗
PubMed1985

Characterization of beta-glucosidase as a peripheral enzyme of lysosomal membranes from mouse liver and purification.

Lysosomal membrane fractions were prepared from lysosomes of mouse liver by freeze-thawing in a hypotonic buffer: 54% of beta-glucosidase [EC 3.2.1.45] in lysosomes was associated with the membrane fractions, whereas 96% of beta-glucuronidase [EC 3.2.1.31] was recovered in the soluble fractions of lysosomes. beta-glucosidase was solubilized by pH 9.5 treatment or by Triton treatment of membranes. The enzyme solubilized with alkali and concentrated with (NH4)2SO4 was rapidly inactivated in a solution of pH 9.5, but could be protected against inactivation by acidic detergent. Gel filtration analysis indicated that beta-glucosidase was in an aggregated form at neutral pH and could be disaggregated by alkali and detergents. The enzyme dissociated with detergents also showed a higher activity than the alkali-treated enzyme. These results suggested that beta-glucosidase is a peripheral enzyme bound to acidic lipids in membranes. beta-Glucosidase was purified to apparent homogeneity by (NH4)2SO4 fractionation and chromatographies with Sephacryl S-300, hydroxylapatite and cation exchangers in the presence of detergents. The catalytic activity of the purified enzyme was maximally stimulated by phosphatidylserine and heat-stable protein in the presence of a low concentration of Triton X-100. The stimulation was mainly due to an increase in Vmax.

Animals↗
PubMed1986

Isolation and characterization of three alpha-glucosidases from the Japanese quail.

We have defined one type of acid alpha-glucosidase and two types of neutral alpha-glucosidases from quail skeletal muscle on the basis of differences in the elution patterns on a DEAE-cellulose column. The appearance of the two neutral alpha-glucosidase isoenzymes was age-dependent. A decrease in acid alpha-glucosidase activity was demonstrated in Japanese quails with glycogenosis type II. The characteristics of these three alpha-glucosidase isoenzymes are described.

Age Factors↗
PubMed1981

Prenatal diagnosis of Gaucher disease. Assay of the beta-glucosidase activity in amniotic fluid cells cultivated in two laboratories with different cultivation conditions.

Sixteen pregnancies at risk for Gaucher disease -- six with the Norrbottnian form, one with a juvenile form with a similar clinical course to the patients from Norrbotten and nine with the infantile from -- have been monitored by the assay of beta-glucosidase activity in cultivated amniotic fluid cells with natural labelled glycosylceramide as substrate. Two methods of cultivation were compared in respect of their effect on the activity of lysosomal enzymes. No significant difference was found between the two marker enzymes, beta-galactosidase and N-acetyl-beta-glucosaminidase, but the beta-glucosidase activity was significantly higher in the cells cultivated with one of the methods. In four of the pregnancies at risk, the beta-glucosidase activity in the cultivated amniotic fluid cells was less than 5% of that in the two control materials. These fetuses were regarded as affected with Gaucher disease and were aborted. Differentiation between controls and Gaucher heterozygotes was not possible in cultivated amniotic fluid cells. The diagnosis of Gaucher disease in the amniotic fluid cells was confirmed in three of the four cases by the assay of the beta-glucosidase activity in the liver nd brain of the aborted fetuses. The glucosylceramide content of the liver from two aborted fetuses was not augmented. The beta-glucosidase activity was examined in seven placentas from pregnancies at risk for Gaucher disease and found to be in agreement with that in the cultivated amniotic fluid cells.

Amniotic Fluid↗
PubMed1978

Characterization of beta-glucosidase isoenzymes possibly involved in lignification from chick pea (Cicer arietinum L.) cell suspension cultures.

Crude cell wall preparations from Cicer arietinum L. cell suspension cultures show high activity for the hydrolysis of coniferyl alcohol beta-D-glucoside (coniferin). Various beta-glucosidase activities could be solubilized from these preparations by 0.5 M NaCl treatment and one of these could be shown to possess a high activity for the hydrolysis of coniferin. The enzyme activities were purified to near homogeneity by Sephadex G-200 and CM-Sephadex chromatography. Isoelectric focussing indicated the occurrence of beta-glucosidase isoenzymes with identical catalytic activity (pI 8.5-10). Molecular weights were determined as 110 000, with two subunits of 63 000 and 43 000. Maximum hydrolytic activity is at pH 5. The beta-glucosidase isoenzymes catalyze the hydrolysis of various beta-glucosides with aromatic aglycone structure and different sugar moieties. However, coniferin has been found to be one of the best substrates (km = 0.8 mM; V = 6 mumol.min-1.mg protein-1) for these beta-glucosidase isoenzymes. The data suggest that beta-glucosidase-catalyzed reaction might be involved in lignification of these plant cell cultures.

Cinnamates↗
PubMed1984

Purification by affinity chromatography of glucosidase I, an endoplasmic reticulum hydrolase involved in the processing of asparagine-linked oligosaccharides.

Trimming glucosidase I and II have been solubilized from crude calf liver microsomes and partially enriched by a fractionated extraction procedure applying different concentrations of nonionic detergent and salt. The pH optimum of both enzymes was found to be close to 6.2, which discriminates them from hydrolases of lysosomal origin acting on p-nitrophenyl glycosides with the highest rate at more acidic pH. Glucosidase I and II and the nonspecific alpha-glucosidase(s) were inhibited by 1-deoxynojirimycin with median inhibitory concentration of 3 microM, 20 microM, 12 microM, respectively. Discrimination between these enzymes was strongly enhanced by N-alkylation of 1-deoxynojirimycin and formed the basis for the design of the affinity ligand. Glucosidase I has been purified to homogeneity by affinity chromatography on AH-Sepharose 4B with N-carboxypentyl-1-deoxynojirimycin as ligand. Sodium dodecyl sulfate gel electrophoresis of the purified enzyme revealed a subunit molecular mass of about 85 kDa. The molecular mass of the native enzyme, determined by gel chromatography, was approximately equal to 320-350 kDa, pointing to the association of subunits to a tetramer. Glucosidase I is rather stable when stored at 4 degrees C in the presence of detergent (t 1/2 approximately equal to 20 days) and showed high specificity for the hydrolysis of the terminal (alpha 1,2)-linked glucose residue in the natural substrate Glc3-Man9-(GlcNAc)2.

1-Deoxynojirimycin↗
PubMed1986

Transport and processing of endocytosed lysosomal alpha-glucosidase in cultured human skin fibroblasts.

In the present study we have characterised the molecular products that arise from processing of a precursor form of alpha-glucosidase isolated from urine after endocytosis at 37 degrees C by cultured human skin fibroblasts. The urinary precursor (Mr 110 000) was processed to forms with Mr of 100 000, 80 000 and 74 000. These forms were approximately 4000 Da larger than the corresponding forms of endogenously synthesized alpha-glucosidase. Digestion of the different forms of the enzyme with endoglycosidase F showed that the differences in apparent molecular mass between the exogenous and corresponding endogenous forms were due to difference in glycosylation. Intracellular transport of endocytosed alpha-glucosidase was followed by incubating fibroblast homogenates with glycyl-L-phenylalanine-beta-naphthylamide (Gly-Phe-NH-Nap), which leads to specific lysis of lysosomes. Transport to the lysosomes was a fast process: within 45 min after endocytosis more than 50% of the enzyme was present in the lysosome. The first step in the processing of endocytosed alpha-glucosidase started in a Gly-Phe-NH-Nap-insensitive (prelysosomal) compartment, but further processing of the enzyme to lower-Mr forms was coupled to transport to the lysosomes. Processing of alpha-glucosidase after uptake at 20 degrees C was also studied. At this temperature the enzyme accumulated in an organelle with a low buoyant density, presumably the endosome; this compartment appeared to be heterogeneous, ranging in density from 1.04 g/ml to 1.08 g/ml. Under these conditions only the first step in the processing of the enzyme occurred. It is concluded that endocytosed enzyme is processed more rapidly than endogenously synthesized enzyme owing to the fact that endocytosed enzyme is transported more rapidly to the lysosomes. Furthermore, processing may start in a prelysosomal organelle.

Biological Transport↗
PubMed1987

beta-Glucosidases from cellulolytic fungi Aspergillus terreus, Geotrichum candidum, and Trichoderma longibrachiatum as typical glycosidases.

By ethanol precipitation (v/v) and chromatography on Sephadex SP, DEAE (or DEAE-cellulose), and G-200 beta-glucosidases (EC 3.2.1.21) from the culture filtrates of cellulolytic fungi Aspergillus terreus, Geotrichum candidum, and Trichoderma longibrachiatum grown on the medium with cellulose containing materials were isolated. The enzymes were homogenous as shown by different techniques. The substrate specificities of the obtained enzymes were studied. beta-Glucosidases had higher affinity for p-nitrophenyl-beta-D-glucopyranoside than for cellobiose (Km 1.25, 0.34, 0.20 and 5.4, 2.0, 1.2 mM, respectively) and were able to hydrolyze both laminaribiose and gentiobiose; but they were unable to cleave cotton fiber, carboxymethylcellulose, and other glycans to reducing sugars. They showed transglycosylase activity. Ki values for arylglucosidase activity of beta-glucosidases from A. terreus, G. candidum, and T. longibrachiatum in the presence of either glucose or glucono-1,5-lactone were 12.2, 6.0, 2.1 and 0.20, 0.19, 0.07 mM, respectively. The Mr's were estimated by gel filtration and by sedimentation equilibrium centrifugation to 200,000, 200,000, 350,000, respectively. The isoelectric points of beta-glucosidases were 4.8, 5.9, and 4.2, respectively. The optimum temperatures and pH's were 60, 50, and 50 degrees C and at pH 4.5, 4.5, and 4.8-5.7, respectively. These properties appear to relate beta-glucosidases obtained in the present study to typical glycosidases.

Aspergillus↗
PubMed1987

Regulation of beta-glucosidase in Bacteroides ruminicola by a different mechanism: growth rate-dependent derepression.

Bacteroides ruminicola B(1)4, a predominant ruminal and cecal bacterium, was grown in batch and continuous cultures, and beta-glucosidase activity was measured by following the hydrolysis of p-nitrophenyl-beta-glucopyranoside. Specific activity was high when the bacterium was grown in batch cultures containing cellobiose, mannose, or lactose (greater than 286 U/g of protein). Activity was reduced approximately 90% when the organism was grown on glucose, sucrose, fructose, maltose, or arabinose. The specific activity of cells fermenting glucose was initially low but increased as glucose was depleted. When glucose was added to cultures growing on cellobiose, beta-glucosidase synthesis ceased immediately. Catabolite repression by glucose was not accompanied by diauxic growth and was not relieved by cyclic AMP. Since glucose-grown cultures eventually exhibited high beta-glucosidase activity, cellobiose was not needed as an inducer. Catabolite repression explained beta-glucosidase activity of batch cultures and high-dilution-rate chemostats where glucose accumulated, but it could not account for activity at slow dilution rates. Maximal beta-glucosidase activity was observed at a dilution rate of approximately 0.35 h-1, and cellobiose-limited chemostats showed a 15-fold decrease in activity as the dilution rate declined. An eightfold decline was observed in glucose-limited chemostats. Since inducer availability was not a confounding factor in glucose-limited chemostats, the growth rate-dependent derepression could not be explained by other mechanisms.

Animals↗
PubMed1987

beta-Glucosidase in Candida albicans and its application in yeast identification.

In this report we attempt to explain the discrepancy between beta-glucosidase (EC 3.2.1.21) activity in Candida albicans as measured by commercial kits and that found in an experimental assay. beta-Glucosidase activity in American and Israeli isolates of C. albicans was evaluated with the API ZYM and YeastIdent systems (Analytab Products) and with experimental biochemical assays. Activity was found with whole cells and cell extracts of isolates from both sources. The greatest beta-glucosidase activity was found at pH 5.0 and with p-nitrophenyl-beta-glucopyranoside (PNP-BDG) as the substrate. In assays with beta-naphthyl-beta-D-glucopyranoside and 6-bromo-2-naphthyl-beta-D-glucopyranoside (6-Br-2-naphthyl-BDG), no enzyme activity was detected in whole cells and only limited activity was found in cell extracts of isolates from both sources. In studies with PNP-BDG at pH 5.0 and 7.5, 29 to 38% less activity was found at both pHs with American whole cells, and minor activity (20%) was found at pH 7.5 with isolates from both sources. Because assays with PNP-BDG in cell extracts of isolates from both sources showed no significant differences in activity, the more limited beta-glucosidase activity in American whole cells was most likely due to less efficient transport. Because the API ZYM system uses 6-Br-2-naphthyl-BDG as the substrate and because the substrate is buffered at pH 7.5 in the API YeastIdent kit, both systems appear to be of limited value for the detection of beta-glucosidase activity in C. albicans.

Candida albicans↗
PubMed1985

Serum neutral alpha-D-glucosidase from patients with cystic fibrosis and chronic pulmonary disease.

Previous studies have indicated that alpha-D-glucosidase activity is increased and exhibits abnormal properties in tissues from patients with cystic fibrosis (CF). In the present investigation serum alpha-D-glucosidase from patients with CF and from patients with chronic pulmonary disease (e.g. asthma and bronchiectasis) has been studied to determine the specificity of the alpha-D-glucosidase alteration(s) in CF sera. Both groups of patients have elevated alpha-D-glucosidase activity levels and similarly abnormal isoelectric focusing profiles with significantly less activity associated with acidic enzymatic forms (i.e. having isoelectric points below 4.8). These results suggest that the abnormalities of CF serum alpha-D-glucosidase may be secondary to chronic pulmonary disease and emphasize the importance of including appropriate pathological controls in biochemical studies on CF.

Adolescent↗
PubMed1998

Purification and properties of an amylopullulanase, a glucoamylase, and an alpha-glucosidase in the amylolytic enzyme system of Thermoanaerobacterium thermosaccharolyticum.

Thermoanaerobic bacteria are of considerable interest as producers of thermostable amylolytic enzymes. The soluble amylolytic enzyme system of Thermoanaerobacterium thermosaccharolyticum DSM 571 was fractionated into a pullulanase, a glucoamylase, and an alpha-glucosidase. The enzymes were purified to homogeneity and their physical and catalytic properties were studied. The pullulanase, which cleaved both alpha-1,4- and alpha-1,6-glucosidic bonds, was an amylopullulanase closely related to similar enzymes from other thermoanaerobic bacteria. Partial amino acid sequences of the glucoamylase were identical with the corresponding sequences deduced from the cga gene encoding the glucoamylase from Clostridium sp. strain G0005. The alpha-glucosidase was identified as an isomaltase belonging to a group of structurally related exo-alpha-1,4-glucosidases and oligo-1,6-glucosidases from bacilli. Comparison of enzyme activities indicated that the glucoamylase had the major amylolytic activity of T. thermosaccharolyticum, with amylopullulanase and alpha-glucosidase assisting in the cleavage of alpha-1,6-glucosidic bonds.

Amino Acid Sequence↗