Showing papers on "Amylase published in 1987"
TL;DR: In this article, the authors measured polysaccharide-degrading activity in different fractions of human faeces and found that bacterial poly-saccharidases and glycosidases were primarily associated with the washed bacterial fractions.
Abstract: Measurements of polysaccharide-degrading activity in different fractions of human faeces showed that bacterial polysaccharidases and glycosidases were primarily associated with the washed bacterial fractions. Amylase, pectinase and xylanase were the major polysaccharide-hydrolysing enzymes detected, whilst α-L-arabinofuranosidase, β-D-xylosidase, β-D-galactosidase and β-D-glucosidase were the most active glycosidases. Starch and 3 non-starch polysaccharides (NSP; pectin, xylan and arabinogalactan) were fermented by mixed populations of human faecal bacteria in batch culture. Detailed carbohydrate analysis demonstrated that starch and pectin were the most rapidly degraded substrates and that arabinogalactan and the relatively insoluble polysaccharide xylan were broken down more slowly. Free sugars and oligosaccharides did not accumulate in culture media with any polysaccharide tested. Time-course measurements of polysaccharide remaining in the batch culture fermentations showed that the arabinose side chains of pectin, xylan and arabinogalactan were co-utilised with the backbone sugars. In these cultures, polysaccharide-degrading activity was mainly cell-associated, but extracellular polysaccharidase activity increased as the fermentations progressed. Molar ratios of acetate, propionate and butyrate produced in these experiments were dependent upon the polysaccharide substrate tested. Molar ratios of acetate, propionate and butyrate in the starch, arabinogalactan, xylan and pectin fermentations were 50:22:29, 50:42:8, 82:15:3, and 84:14:2, respectively. The presence of starch did not inhibit the breakdown of arabinogalactan, xylan or pectin by faecal bacterial, providing evidence that multicomponent substrate utilisation occurs when complex populations of faecal bacteria are provided with mixed polysaccharide substrates.
273 citations
TL;DR: In this paper, the authors found that the digestibility of starch was poor and highly variable when 3-week-old chickens were fed unpelleted wheat diets, but improved with age.
Abstract: Apparent metabolizable energy (AME) of wheat for 6-week-old male broiler chickens was highly correlated with starch digestibility when pelleted diets containing 820 g wheat per kg were fed. Starch isolated from low-AME wheats was hydrolysed in vitro by chicken pancreatic amylase as rapidly as starch from high-AME wheats. When included in semi-purified diets the isolated starches were completely digestible. Digestibility of starch was poor and highly variable when 3-week-old chickens were fed unpelleted wheat diets, but improved with age. Oat hulls improved the digestibility of starch in young chickens fed unpelleted diets.
169 citations
TL;DR: The presence and localization of acid and alkaline phosphatase, non-specific proteases, aminopeptidase, amylase, Non-specific esterase and lipase was investigated by histoenzymologic methods in fed and fasting turbot from day 1 to day 40 post-hatching and compared with published data.
Abstract: The presence and localization of acid and alkaline phosphatase, non-specific proteases, aminopeptidase, amylase, non-specific esterase and lipase was investigated by histoenzymologic methods in fed and fasting turbot from day 1 to day 40 post-hatching and compared with published data. Alkaline phosphatase and aminopeptidase activities were delected at day 1 in the distal region of the developing digestive tube. At day 3 (opening of the mouth) aminopeptidase and alkaline phosphatase activities were found all along the intestine. Sites of non-specific esterase and protease activities became apparent in the digestive tract at days 2 and 3 respectively. Amylase was present in the exocrine pancreas at day 3 and in the lumen of the intestine at day 4. Acid phosphatase was active in the cellular structure surrounding the yolk stores and in the lipid droplets at day 1 and in the intestinal epithelium at day 3. Lipase was found at day 15 when the larvae metamorphose into juveniles.
All the investigated enzymes were detected in fasting animals, except for lipase. However, the intensities of the enzymatic activities were weaker in the fasting specimens relative to the fed specimens between days 7 and 10.
150 citations
TL;DR: The formation of in vitro resistant starch (RS) during autoclaving and freeze-drying of wheat starch suspension was evaluated in this article, showing that RS formed during heat-treatment should be regarded as an easily fermentable dietary fibre component.
137 citations
TL;DR: Pancreas allograft rejection in dogs with pancreati-cocystostomy can be predicted in advance of hyperglycemia by monitoring the urinary amylase (UA) concentration (U/L); five grafts are currently functioning; 3 recipients had no rejection episodes and their UA values ranged from 30,000 to 100,000 U/24 hr during their entire postoperative course.
Abstract: Pancreas allograft rejection in dogs with pancreati-cocystostomy can be predicted in advance of hyperglycemia by monitoring the urinary amylase (UA) concentration (U/L): In initial experiments, UA values declined to <1000 1.3±0.2 days before hyperglycemia in non-immunosuppressed dogs, 3.3±1.0 days i
127 citations
TL;DR: Dye experiments with Musca domestica larvae suggested that bacteria are killed at mid-midgut through the combined action of low pH, lysozyme and pepsin, which led to the proposal that the adaptive features of the digestion of housefly maggots are thought to be derived characters evolved from a putative Diptera ancestor.
111 citations
TL;DR: In this paper, the effects of phytate and other myo-inositol phosphate esters (containing one or more phosphate groups) on α-amylase digestion of potato starch were evaluated by an in vitro procedure.
Abstract: The effects of phytate and other myo-inositol phosphate esters (containing one or more phosphate groups) on α-amylase digestion of soluble potato starch were evaluated by an in vitro procedure. Human salivary or Bacillus subtilisα-amylase was treated with either 2 mM or 5 mM phytate, myo-inositol-2-monophosphate (l–2-MP), or phytate hydrolyzed to various degrees, and then incubated at 37°C with the starch at pH 4.15 or 6.90. Starch digestion varied with degree of phosphorylation of inositol, inositol phosphate ester concentration, pH and enzyme source. At pH 4.15, phytate (2 mM) and I-2-MP (2 mM) reduced starch digestion by salivary α-amylase to 8.5 and 78.3%, respectively, of the control.
100 citations
TL;DR: Amylase should not be measured in postprandial studies of pancreatic secretion in humans without correction for salivary amylase, according to an inhibitor assay technique.
Abstract: With an inhibitor assay technique rates of passage of salivary and pancreatic isoamylase through the jejunum were measured in six healthy volunteers after different liquid, intragastric meals. In all subjects and in 13/17 experiments, more than 2500 units of salivary amylase were passed over 200 postcibal minutes. Salivary amylase comprised 13.8±3.9% (X ±SEM) of the total amylase and appeared predominantly as single, distinct peak. The inhibitor method was validated by isoelectric focusing (r=0.988;P<0.001;N=7). The frequency of detection of salivary amylase in gastric or jejunal samples fell as gastric pH fell below 3.0.In vitro, amylase was inactivated in gastric juice as pH fell between 3.8 and 3.3. Salivary amylase accounted for 11% of total amylase output in a normal and 27% in an achlorhydric subject after a hamburger meal. We conclude that amylase should not be measured in postprandial studies of pancreatic secretion in humans without correction for salivary amylase.
96 citations
TL;DR: In this article, the authors provide a simple relationship among a-amylase activities, which allows comparison of the enzyme activities in the literature, even though the assay methods and definitions of an enzyme unit are different, enzyme activities can be correlated as a function of incubation temperature, incubation time, dilution factor and measurement methods.
Abstract: a-Amylase enzymes (1,4-a-~-glucanohydrolase, E.C.3.2.1.1) catalyze the hydrolysis of a l ,4 glucosidic linkages in polysaccharides of three or more a-I, 4-linked D-glucose units to produce maltose and larger oligosaccharides. 1 ~ 2 Since there are many different assay methods and definitions for a unit of a-amylase enzyme activity, it is almost impossible to compare enzyme activities. One reason is that most groups working with a-amylase developed their own enzyme assay systems, each with its own unit of a ~ t i v i t y . ~ The objective of this communication is to provide a simple relationship among a-amylase activities, which allows comparison of the enzyme activities in the literature. Even though the assay methods and definitions of an enzyme unit are different, enzyme activities can be correlated as a function of incubation temperature, incubation time, dilution factor, and measurement methods. This result will be useful in finding a microorganism or culture conditions which give the highest enzyme activity.
93 citations
TL;DR: A new Clostridium strain was isolated on starch and induced the synthesis of alpha-amylase and pullulanase, which occurred predominantly in the exponential phase while glucose, ribose, fructose, and lactose did not.
Abstract: A new Clostridium strain was isolated on starch at 60 degrees C. Starch, pullulan, maltotriose, and maltose induced the synthesis of alpha-amylase and pullulanase, while glucose, ribose, fructose, and lactose did not. The formation of the amylolytic enzymes was dependent on growth and occurred predominantly in the exponential phase. The enzymes were largely cell bound during growth of the organism with 0.5% starch, but an increase of the starch concentration in the growth medium was accompanied by the excretion of alpha-amylase and pullulanase into the culture broth; but also by a decrease of total activity. alpha-Amylase, pullulanase, and alpha-glucosidase were active in a broad temperature range (40 to 85 degrees C) and displayed temperature optima for activity at 60 to 70 degrees C. During incubation with starch under aerobic conditions at 75 degrees C for 2 h, the activity of both enzymes decreased to only 90 or 80%. The apparent K(m) values of alpha-amylase, pullulanase, and alpha-glucosidase for their corresponding substrates, starch, pullulan, and maltose were 0.35 mg/ml, 0.63 mg/ml, and 25 mM, respectively.
84 citations
TL;DR: The production of α-amylase, pullulanase, and α-glucosidase and the formation of fermentation products by the newly isolated thermophilic Clostridium sp.
Abstract: The production of α-amylase, pullulanase, and α-glucosidase and the formation of fermentation products by the newly isolated thermophilic Clostridium sp strain EM1 were investigated in continuous culture with a defined medium and an incubation temperature of 60°C Enzyme production and excretion were greatly influenced by the dilution rate and the pH of the medium The optimal values for the formation of starch-hydrolyzing enzymes were a pH of 59 and a dilution rate of 0075 to 010 per h Increase of the dilution rate from 01 to 03 per h caused a drastic drop in enzyme production The ethanol concentration and optical density of the culture, however, remained almost constant Growth limitation in the chemostat with 1% (wt/vol) starch was found optimal for enzyme production Under these conditions 2,800 U of pullulanase per liter and 1,450 U of α-amylase per liter were produced; the amounts excreted were 70 and 55%, respectively
TL;DR: Four major forms of barley β-amylase have been purified in the presence of 0.1m-thiol from extracts of flour fractionated by ammonium sulfate precipitation and chromatography on DEae-cellulose and DEAE-Fractogel.
Abstract: Four major forms of barley β-amylase have been purified in the presence of 0.1m-thiol from extracts of flour fractionated by ammonium sulfate precipitation and chromatography on DEAE-cellulose and DEAE-Fractogel. The β-amylases were NH2-terminally blocked, single polypeptide chains of approx. Mr 59,700, 58,000, 56,000 and 54,000, with corresponding pI 5.2, 5.3, 5.5 and 5.7. All forms displayed optimal activity on soluble starch between pH 4.5 and 7.5; all Km and Vmax values were 2.5 mg·ml−1 and 17 μmol maltose·min−1·(nmol protein)−1, respectively.
TL;DR: A murine pancreatic amylase gene, Amy-2.2y, is characterized, whose promoter sequence is 30% divergent from those of previously sequenced amyl enzyme genes, and which contains the sequences required for tissue-specific and hormonally regulated expression.
Abstract: The regulatory properties of mouse pancreatic amylase genes include exclusive expression in the acinar cells of the pancreas and dependence on insulin and glucocorticoids for maximal expression. We have characterized a murine pancreatic amylase gene, Amy-2.2y, whose promoter sequence is 30% divergent from those of previously sequenced amylase genes. To localize sequences required for tissue-specific and hormone-dependent activation, we established two lines of transgenic mice. The first line contained a single copy of the complete Amy-2.2y gene as well as 9 kilobases of 5'-flanking sequence and 5 kilobases of 3'-flanking sequence. The second line carried a minigene which included 208 base pairs of 5'-flanking sequence and 300 base pairs of 3'-flanking sequence. In both lines the transgene was expressed at high levels exclusively in the pancreas. Both constructs were dependent on insulin and induced by dexamethasone. Thus, the transferred genes contained the sequences required for tissue-specific and hormonally regulated expression.
TL;DR: There is a difference, of the order of 100-fold, in the mRNA levels between larvae that are fed 10% glucose and larvae of the same wild-type strain that are feeding an equivalent diet lacking glucose, indicating that the glucose effect, which was previously characterized at the level of enzyme activity, probably reflects a change in the transcriptional activity of the amylase gene.
Abstract: Amylase-specific cDNA probes were used to assay amylase mRNA levels in third-instar larvae of Drosophila melanogaster. It is shown that there is a difference, of the order of 100-fold, in the mRNA levels between larvae that are fed 10% glucose and larvae of the same wild-type strain that are fed an equivalent diet lacking glucose. In fact, the glucose-fed larvae have barely detectable levels of amylase mRNA. This large difference in transcript abundance indicates that the glucose effect, which we previously characterized at the level of enzyme activity, probably reflects a change in the transcriptional activity of the amylase gene.
TL;DR: Evidence is provided that blockage of gap junctional coupling increases the basal secretion of exocrine pancreas as well as the response of the gland to a variety of secretagogues.
Abstract: Dispersed pancreatic acini were studied to assess the function of junctional coupling between adult secretory cells. Nonstimulated control cells were extensively coupled to their neighbors throughout each acinus. Addition of heptanol caused their uncoupling and increased their basal amylase release. Neurotensin, secretin, and vasoactive intestinal peptide (VIP) stimulated amylase secretion without uncoupling acinar cells. Heptanol rapidly and markedly uncoupled the neurotensin-, secretin-, and VIP-stimulated acinar cells and increased their amylase secretion in an additive manner. By contrast, the secretory response to carbamoylcholine (carbachol), a secretagogue that, alone, uncoupled acinar cells, was not affected by heptanol. Basal as well as neurotensin-, secretin-, and VIP-stimulated output returned to the lower control values following removal of heptanol and recovery of normal coupling. The data provide evidence that blockage of gap junctional coupling increases the basal secretion of exocrine pancreas as well as the response of the gland to a variety of secretagogues.
TL;DR: In this article, the starch contents of three cultivars of cassava were determined in cooked and uncooked samples with and without removal of alcohol-soluble solids using Hydrochloric acid and amyloglucosidase methods of hydrolysis.
Abstract: The starch contents of three cultivars of cassava were determined in cooked and uncooked samples with and without removal of alcohol-soluble solids. Hydrochloric acid and amyloglucosidase methods of hydrolysis were used. Hydrolysates were analysed using glucose-specific (glucose oxidase) and non-specific (ferricyanide reduction) methods. Statistical analysis of the results obtained indicated that there were no significant differences between the methods of hydrolysis and sugar analysis. The increased cost of using an enzymic method of starch analysis appears not to be justified for the determination of starch in cassava, unlike a number of other starch sources. The starch values obtained by enzymic hydrolysis of uncooked samples were significantly lower than for cooked samples. The percentage of uncooked cassava starch susceptible to enzymic degradation varied with cultivar from 14.0 to 46.88%. In view of the use of unprocessed/ungelatinised cassava chips or partly gelatinised cassava pellets for animal feed, further research into cultivar variation of starch susceptibility to enzymic degradation is required.
TL;DR: The close similarity of these two genes, as compared with mouse pancreatic and salivary amylase genes, suggests that during evolution, the divergence into the two amyl enzyme genes may have occurred after the divergence of mice and man.
TL;DR: The ratio of buffer to wheat bran, incubation temperature and initial pH influence α-amylase production by Bacillus megaterium 16M under solid state fermentation as discussed by the authors.
Abstract: The ratio of buffer to wheat bran, incubation temperature and initial pH influence α-amylase production byBacillus megaterium 16M under solid state fermentation. The enzyme, with pH and temperature optima at 6.0 and 70°C, is formed at a level of 30,000 units/g dry bacterial bran without coproduction of proteases and cellulases.
TL;DR: Amylase isozymes from the adult rice weevil were purified by high-performance liquid chromatography (HPLC) on a Synchropak AX-300 analytical ion exchange column and significant differences were found in the sensitivity of RW-1 and RW-2 to several major inhibitor fractions.
TL;DR: The results show that wheat bran intake induced an increase in the volume and protein output of the pancreatic juice secreted in a 24-hour period, whereas protein concentration decreased.
Abstract: The aim of this study was to determine the effect of wheat bran consumption on exocrine pancreas secretion in pigs. Sixteen Large-White pigs were divided into two groups. The first group (control) was fed a diet without wheat bran and the second one (experimental) a diet containing 40% wheat bran. After one week the animals were fitted with two permanent fistulae (in the pancreatic duct and the duodenum) and/or with a catheter in a carotid artery. After an 8-day recovery period, pancreatic secretion (volume, protein content and output, chymotrypsin, trypsin, lipase and amylase activities) and plasma levels of some gastro-intestinal peptides [secretin, cholecystokinin (CCK), vasoactive intestinal peptide (VIP), somatostatin and pancreatic polypeptide (PP)] were measured over an experimental period of 5 days. The results show that wheat bran intake induced an increase in the volume (+ 115%) and protein output (+ 36%) of the pancreatic juice secreted in a 24-hour period, whereas protein concentration decreased. All enzyme activities were enhanced by wheat bran. The plasma levels of secretin, VIP, somatostatin and PP were higher in the experimental than in the control group. On the contrary, plasma CCK levels were not affected by wheat bran consumption.
TL;DR: Serum amylase and lipase are frequently elevated in patients with CRF in the absence of clinical pancreatitis, but the presence of pancreatic enzymes in the peritoneal fluid may suggest coexistent pancreatitis.
Abstract: • Serum was obtained from 55 patients, including 43 with stable chronic renal failure (CRF) (28 receiving chronic hemodialysis [CHD] and 15 receiving chronic ambulatory peritoneal dialysis [CAPD]), nine with peritonitis receiving CAPD, and three with pancreatitis receiving CAPD. Total serum amylase activity, lipase activity, isoamylase fractionation, and lipase concentration were used to measure pancreatic enzymes. Amylase activity was increased in 35 of 43 patients with CRF but was greater than threefold elevated in only three. Pancreatic isoamylase activity was greater than 80% in only one patient with CRF but was greater than 80% in all three patients with pancreatitis receiving CAPD. Lipase activity was increased in 26 patients and lipase concentration was elevated in 27. Peritoneal fluid from three patients with pancreatitis receiving CAPD contained high levels of amylase. Serum amylase and lipase are frequently elevated in patients with CRF in the absence of clinical pancreatitis. However, serum amylase activity greater than threefold elevated or the presence of pancreatic enzymes in the peritoneal fluid may suggest coexistent pancreatitis. (Arch Intern Med1987;147:537-539)
TL;DR: In this article, the effect of polyphenols on the rate and extent of starch digestion as well as on fiber degradation was studied in vitro, and it was shown that polyphenolic acid only had negligible influence on the enzyme activity of the amylases tested.
Abstract: The effect of phytic acid and polyphenols on the rate and extent of starch digestion as well as on fiber degradation was studied in vitro. Addition of phytic acid only had negligible influence on the enzyme activity of the amylases tested. In contrast, enzymes concerned with starch hydrolysis in the digestive channel (α‐amylase, amyloglucosidase/maltase) were inhibited by tannic acid, and to some extent also by catechin. Furthermore, tannic acid reduced the total recovery of starch during enzymic starch analysis. The activity of cellulases and hemicellulases was not affected by phytic acid or catechin. However, the degradation of cellulose powder was inhibited by tannic acid, whereas no inhibition could be observed with carboxymethyl‐cellulose as substrate. (Less)
Patent•
10 Jul 1987
TL;DR: In this paper, pathogenic bacteria and viruses have been encapsulated in a pregelatinized starch matrix without the use of chemical crosslinking agents, which can be formulated either for recovery of dry granules or as sprayable liquids.
Abstract: Biological control agents such as pathogenic bacteria and viruses have been encapsulated in a protective, starch matrix without the use of chemical crosslinking agents. The agent is blended into a dispersion of pregelatinized starch, which is thereafter subjected to conditions suitable for retrogradation. Dispersions can be formulated either for recovery of dry granules or as sprayable liquids. Encapsulated products are useful in controlling insects and other pest species having chewing mouth parts and amylase digestive enzymes.
TL;DR: The results indicate that treatment with camostate induces pancreatic hypertrophy and hyperplasia, and that the secretory function of the hypertrophied pancreas is quantitatively but not qualitatively altered.
Abstract: Pancreatic exocrine function in rats given synthetic protease inhibitor camostate (200 mg/kg body weight) perorally once daily for 10 days was investigated. Pancreatic wet weight was significantly increased in the camostate-treated rats. The increase in pancreatic weight was associated with pronounced hypertrophy and moderate hyperplasia. Total amylase, trypsin, and lipase contents in the pancreas were also increased in the camostate-treated group compared with the control rats. Secretory patterns of pancreatic juice and amylase in response to caerulein were similar in both groups, whereas the dose-response curve for pancreatic juice secretion in the camostate-treated rats was shifted tenfold toward higher concentrations of caerulein. Basal and caerulein-stimulated flow rates of pancreatic juice were significantly greater in the camostate-treated rats than the control rats, although both groups showed a threefold increase over basal secretion in response to maximal stimulation. Amylase outputs in basal state and in response to submaximal doses of caerulein were significantly lower, whereas those to maximal and supramaximal doses were significantly greater in the camostate-treated animals than that in the control rats. These results indicate that treatment with camostate induces pancreatic hypertrophy and hyperplasia, and that the secretory function of the hypertrophied pancreas is quantitatively but not qualitatively altered.
TL;DR: Absolute rates of synthesis of total pancreatic secretory proteins, as expressed with regard to the DNA content of the tissue, indicated that biosynthesis of all secretory pancreatic proteins was stimulated by hyperlipidic diets.
Abstract: The effect of ingesting isocaloric and isonitrogenous diets with increasing amounts of lipid (0-30%) and consequently decreasing amounts of carbohydrates (68.7-1.25%) on the exocrine pancreas was studied in adult male Wistar rats. Pancreatic contents of chymotrypsin, lipase and colipase activity, as well as synthesis of amylase, lipase, procarboxypeptidases and individual serine proteases were examined. Lipid-free diets and diets containing 1% lipid were found to have little effect on pancreatic proteins as compared with lipid-rich diets where two distinct patterns of response were observed. Ingestion of diets containing 3-20% lipid resulted in a progressive increase in the activity of lipase, colipase and chymotrypsin up to 2-fold in the first case and 1.6-fold in the two other cases when animals were fed the 20% fat diet. Under the latter conditions, the relative synthesis of secretory proteins, as expressed as percentage of the radioactivity incorporated into individual proteins compared to that incorporated into the total mixture of exocrine proteins, was unchanged for procarboxypeptidases, whereas it was stimulated for lipase (2-fold) and serine proteases (1.6-fold). Amylase relative synthesis progressively decreased as the lipid content of diets increased. Consumption of hyperlipidic diets containing 25% and 30% fat resulted in a further enhancement in the activity of lipase and colipase in the gland in contrast with chymotrypsin activity which was unchanged as compared to the control diet (3% lipid). As far as biosynthesis was concerned, a plateau in the relative synthesis of lipase and serine protease was reached. Amylase relative synthesis further decreased down to 2.2-fold when rats were fed the 30% fat-rich diet whereas that of procarboxypeptidases was markedly increased (about 1.7-fold). Absolute rates of synthesis of total pancreatic secretory proteins, as expressed with regard to the DNA content of the tissue, indicated that biosynthesis of all secretory pancreatic proteins was stimulated by hyperlipidic diets (at least 2-fold with the 30% lipid diet). Consequently, when such an increase was taken into consideration, the absolute synthesis of amylase was found to be unchanged throughout the dietary manipulations, whereas that of lipase, procarboxypeptidases and serine proteases were stimulated by 4.0-fold, 3.4-fold and 3.2-fold, respectively.
TL;DR: A wheat α-amylase cDNA clone has been fused to the phosphoglycerate kinase initiator methionine to enable synthesis in the yeast Saccharomyces cerevisiae of an α-Amylase enzyme that is identical in size to the wild-type α-AMylase.
01 Apr 1987
TL;DR: It is concluded that 2.9 g of the amylase inhibitor given with a meal that contains a mixture of nutrients is effective in increasing carbohydrate tolerance without causing diarrhea and is appropriate for use in studies to determine whether the inhibitor has a beneficial effect in patients with diabetes mellitus or obesity.
Abstract: In previous studies we found that in healthy subjects, 5 and 10 g of a partially purified amylase inhibitor delayed and decreased starch digestion and reduced postprandial plasma glucose after a starch meal but produced diarrhea in two of six and four of six subjects, respectively. Thus, we wondered whether lower doses of the inhibitor, when given with a meal that contained protein and fat as well as carbohydrate, would have the same effect on carbohydrate tolerance without causing diarrhea. Eight healthy subjects were randomized to receive 2.0 or 2.9 g of the inhibitor with a 650-calorie meal that contained carbohydrate, fat, and protein. In comparison with a placebo, ingestion of 2.9 g, but not 2.0 g, of the inhibitor significantly reduced postprandial increases in plasma glucose (P
TL;DR: The results suggest that the two activities are properties of the same protein, representing a novel, thermostable, amylase.
Abstract: Thermostable extracellular alpha-amylase and pullulanase activities of Clostridium thermohydrosulfuricum E 101-69 were characterized in a crude enzyme preparation. The activities responded similarly to temperature and pH, with optima at 85-90 degrees C and pH 5.6. The activities were stable at 65 degrees C, but were inactivated gradually in an identical manner at higher temperatures in the absence of Ca2+ and substrate. Ca2+ stabilized both activities similarly at high temperatures. Ca2+ also stimulated both activities, whereas EDTA reversed this stimulation. The activities were similarly inactivated at pH extremes. The two activities distributed in the same way during isoelectric focusing. The results suggest that the two activities are properties of the same protein, representing a novel, thermostable, amylase.
Patent•
08 Jul 1987TL;DR: An enzyme product comprising a mixture of the.alpha.-amylase from Bacillus licheniformis and the.α-amylases from B. stearothermophilus, which is used for liquefaction of starch or starchy grains is described in this paper.
Abstract: An enzyme product comprising a mixture of the .alpha.-amylase from Bacillus licheniformis and the .alpha.-amylase from B. stearothermophilus, said mixture containing from 10-90% by activity of the Bacillus licheniformis enzyme. The amylase mixture is advantageously used for liquefac-tion of starch or starchy grains.
TL;DR: Starch fractions that are more or less enzyme resistant may behave like dietary fibre, both physiologically and analytically, and should be included in the dietary fibre concept.
Abstract: Starch fractions that are more or less enzyme resistant may behave like dietary fibre, both physiologically and analytically. Ungelatinized granules from potatoes, high amylose maize and green bananas are poorly digested. Starch made resistant to amylase due to new covalent bindings, formed at heat treatment or present in starch derivatives used as food additives, may also be more or less undigestible. "Resistant starch" present in bread and corn flakes is probably retrograded amylose. It is undigestible in the small intestine, but readily degraded by the large bowel microflora. Amylose-lipid complexes seem to be completely absorbed in spite of their resistance to amylase degradation in vitro. Since undigestible starch fractions behave physiologically like non-starch polysaccharides, they should be included in the dietary fibre concept. "Resistant starch" is analysed as glucose based fibre with all current methods except one, which includes an initial DMSO solubilization step.